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Understanding genetic recoding in HIV-1 : the mechanism of -1 frameshiftingMathew, Suneeth Fiona, n/a January 2008 (has links)
The human immunodeficiency virus type 1 (HIV-1) uses a mechanism of genetic recoding known as programmed ribosomal frameshifting to translate the proteins encoded by the pol gene. The pol gene overlaps the preceding gag gene in the -1 reading frame relative to gag. It contains neither a start codon nor an internal ribosome entry site (IRES) to initiate translation of its proteins. Rather the host ribosomes are forced to pause due to tension placed on the mRNA when they encounter a specific secondary structural element in the mRNA. This tension is relieved by disruption of the contacts between the mRNA codons and tRNA anticodons at a �slippery� sequence within the ribosomal decoding centre. Re-pairing of the tRNAs occurs in the new -1 frame after movement of the mRNA backwards by one nucleotide, allowing the ribosome to translate the pol gene as a Gag-Pol polyprotein. A change in ratio of Gag to Gag-Pol proteins affects viral assembly, and most significantly dramatically reduces viral infectivity.
The prevailing model for the mechanism of -1 frameshifting has focussed on a pre-translocational event, where slippage occurs when the slippery sequence is within the ribosomal A and P sites. This model precludes a contribution from the codon immediately downstream of the slippery sequence leading into the secondary structural element. I have termed this the �intercodon�. Often at frameshifting sites it is a termination codon, whereas in HIV-1 it is a glycine codon, GGG. When the intercodon within the frameshift element was changed from the wild-type GGG to a termination codon UGA, the efficiency of frameshifting decreased 3-4-fold in an in vivo assay in cultured human cells. This result mimicked previous data in the group within bacterial cells and cultured monkey COS-7 cells. Changing the first nucleotide of the intercodon to each of the three other bases altered frameshifting to varying degrees, but not following expected patterns for base stacking effects. Such a result would support a post-translocational model for -1 frameshifting. It suggested that the intercodon might be within the ribosomal A site before frameshifting, and that the slippery sequence was therefore within the P and E sites.
This was investigated by modulating the expression of decoding factors for the intercodon - the release factor eRF1 and cognate suppressor tRNAs when it was either of the UGA or UAG termination codons, and tRNA[Gly] for the native GGG glycine codon. These were predicted to affect frameshifting only if slippage were occurring when the ribosomal elongation cycle was in the post-translocational state. Overexpression of tRNA[Gly] gave inconsistent effects on frameshifting in vivo, implying that its concentration may not be limiting within the cell. When eRF1 was overexpressed or depleted by RNAi, significant functional effects of decreased or increased stop codon readthrough respectively were documented. Expression of suppressor tRNAs increased readthrough markedly in a stop codon-specific manner. These altered levels of eRF1 expression were able to modulate the +1 frameshifting efficiency of the human antizyme gene. Overexpression of eRF1 caused significant reduction of frameshifting of the HIV-1 element with the UAG or UGA intercodon. Depletion of the protein by contrast had unexplained global effects on HIV-1 frameshifting. Suppressor tRNAs increased frameshifting efficiency at the UAG or UGA specifically in a cognate manner. These results strongly indicate that a post-translocational mechanism of frameshifting is used to translate the HIV-1 Gag-Pol protein.
A new model (�almost� post-translocational) has been proposed with -1 frameshifting occurring for 1 in 10 or 20 ribosomal passages during the end stages of translocation, because of opposing forces generated by translocation and by resistance to unwinding of the secondary structural element. With translocation still incomplete the slippery sequence is partially within the E and P sites, and the intercodon partially within the A site. The nature of the intercodon influences frameshifting efficiency because of how effectively the particular decoding factor is able to bind to the partially translocated intercodon and maintain the normal reading frame.
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Novel genes in the liver of diabetic psammomys obesus.Southon, Adam, mikewood@deakin.edu.au January 2002 (has links)
Type 2 diabetes mellitus is a metabolic disease characterised by defects in insulin secretion and insulin action and disturbances in carbohydrate, fat and protein metabolism. Hepatic insulin resistance contributes to hyperglycemia and also leads to disturbances in fat metabolism in type 2 diabetes. Psammomys obesus is a unique poly genie animal model of type 2 diabetes and obesity, ideally suited for studies examining physiological and genetic aspects of these diseases.
To identify metabolic abnormalities potentially contributing to the obesity and diabetes phenotype in P. obesus, indirect calorimetry was used to characterise whole body energy expenditure and substrate utilisation. Lean-NGT, obese-IGT and obese-diabetic animals were examined in fed and fasted states and following 14 days of dietary energy restriction.
Energy expenditure and fat oxidation were elevated in the obese-IGT and obese-diabetic groups in proportion to body weight. Glucose oxidation was not different between groups. Obese-diabetic P. obesus displayed elevated nocturnal blood glucose levels and fat oxidation. Following 14 days of dietary energy restriction, body weight was reduced and plasma insulin and blood glucose levels were normalised in all groups. Glucose oxidation was reduced and fat oxidation was increased. After 24 hours of fasting, plasma insulin and blood glucose levels were normalised in all groups. Energy expenditure and glucose oxidation were greatly reduced and fat oxidation was increased. Following either dietary energy restriction or fasting, energy expenditure, glucose oxidation and fat oxidation were not different between groups of P. obesus.
Energy expenditure and whole body substrate utilisation in P. obesus was similar to that seen in humans. P. obesus responded normally to short term fasting and dietary energy restriction. Elevated nocturnal fat oxidation rates and plasma glucose levels in obese-diabetic P. obesus may be an important factor in the pathogenesis of obesity and type 2 diabetes in these animals. These studies have further validated P. obesus as an ideal animal model of type 2 diabetes and obesity.
It was hypothesised that many genes in the liver of P. obesus involved in glucose and fat metabolism would be differentially expressed between lean-NGT and obese-diabetic animals. These genes may represent significant factors in the pathophysiology of type 2 diabetes. Two gene discovery experiments were conducted using suppression subtractive hybridisation (SSH) to enrich a cDNA library for differentially expressed genes.
Experiment 1 used cDNA dot blots to screen 576 clones with cDNA derived from lean-NGT and obese-diabetic animals. 6 clones were identified as overexpressed in lean-NGT animals and 6 were overexpressed in obese-diabetic animals. These 12 clones were sequenced and SYBR-Green PCR was used to confirm differential gene expression. 4 genes were overexpressed (≥1.5 fold) in lean-NGT animals and 4 genes were overexpressed (≥1.5 fold) in obese-diabetic animals.
To explore the physiological role of these genes, hepatic gene expression was examined in several physiological conditions. One gene, encoding thyroxine binding globulin (TBG), was confirmed as overexpressed in lean-NGT P. obesus with ad libitum access to food, relative to both obese-IGT and obese-diabetic animals. TBG expression decreased with fasting in all animals. Fasting TBG expression remained greater in lean-NGT animals than obese-IGT and obese-diabetic animals. TBG expression was not significantly affected by dietary energy restriction. TBG is involved in thyroid metabolism and is potentially involved in the regulation of energy expenditure.
Fasting increased hepatic site 1 protease (SIP) expression in lean-NGT animals but was not significantly affected in obese-IGT and obese-diabetic animals. SIP expression was not significantly affected by dietary energy restriction. SIP is involved in the proteolytic processing of steroid response element binding proteins (SREBP). SREBPs are insulin responsive and are known to be involved in lipid metabolism.
Gene expression studies found TBG and SIP were associated with obesity and diabetes. Future research will determine whether TBG and SIP are important in the pathogenesis of these diseases.
Experiment 2 used SSH and cDNA microarray to screen 8064 clones. 223 clones were identified as overexpressed in lean-NGT P. obesus and 274 clones were overexpressed in obese-diabetic P. obesus (p ≤0.05). The 9 most significantly differentially expressed clones identified from the microarray screen were sequenced (p ≤0.01). 7 novel genes were identified as well as; sulfotransferase related protein and albumin. These 2 genes have not previously been associated with either type 2 diabetes or obesity. It is unclear why hepatic expression of these genes may differ between lean-NGT and obese-diabetic groups of P. obesus. Subsequent studies will explore the potential role of these novel and known genes in the pathophysiology of type 2 diabetes.
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Fine mapping and characterisation of an autoimmune diabetes locus, insulin dependent diabetes 21, (Idd21) on mouse chromosome-18Hollis-Moffatt, Jade Elissa, n/a January 2006 (has links)
Autoimmune disease is comprised of a wide variety of disorders characterised by a loss of self-tolerance towards a target organ or systemic region leading to its eventual destruction. Type 1 diabetes (T1D), autoimmune thyroid disease (AITD) and inflammatory bowel disease (IBD) are debilitating organ-specific disorders. These disorders arise from a combination of genetic factors and environmental triggers. A greater level of basic understanding of these disorders is required to delay and/or prevent their effects. Numerous autoimmune susceptibility loci have been implicated in the development of these disorders, but only a few causative genes have been identified. The aim of this project was to use comparative mapping between the human and mouse genomes to provide a greater understanding of the human autoimmune susceptibility locus, IDDM6, shown to be involved in a number of autoimmune disease conditions.
Hall et al., (2003) previously demonstrated that the mouse autoimmune diabetes locus, Idd21, on distal mouse chr18 contains orthology to human IDDM6, IDDM10, IDDM18 and rat Iddm3. As part of this project the Idd21 locus was fine mapped using the congenic mapping technique. Beginning with the consomic mouse strain, NOD.ABHChr18 (90Mb of Biozzi/ABH-derived diabetes-resistant chr18 introgressed onto a non-obese diabetic (NOD) genetic background), 13 NOD.ABHIdd21 congenic mouse strains were established. The diabetes incidences of these congenic mouse strains were statistically compared stepwise along mouse chr18 and Idd21 was fine mapped to at least four independent autoimmune diabetes loci. Idd21.1 and Idd21.2 were located on distal mouse chr18 in regions orthologous to human IDDM6 and rat Iddm3 and Idd21.3a/b and Idd21.4 were located on proximal mouse chr18 in regions orthologous to human IDDM18 and IDDM10 respectively. Candidate genes of notable interest include Map3k8, Spink5, Cd14, Dcc, Smad4 and 7, Miz1, Nfatc1 and Cd226.
Idd21.1 was further fine mapped. Beginning with the NOD.ABHD18Mit8-D18Mit214[(75-85.1Mb)] (Idd21.1) congenic strain (containing at least 10.1Mb of distal chr18 Biozzi/ABH diabetes-resistant DNA introgressed onto a NOD genetic background), seven subcongenic mouse strains were created. The diabetes incidence of these subcongenic mouse strains were statistically compared stepwise along mouse chr18 and Idd21.1 was fine mapped to at least three independent autoimmune diabetes loci; Idd21.11 (72.6-76.1Mb), Idd21.12a/b (75-76.1Mb and 80.6-81.4Mb) and Idd21.13 (84.8-85.1Mb). Candidate genes of interest in these regions include Dcc, Smad4 and 7, Miz1, Nfatc1, and Cd226.
Functional characterisation of the Idd21.1 locus was performed by adoptively transferring splenocytes from female NOD or NOD.ABHIdd21.1 mice into cohorts of severe combined immune deficient (scid) female mice, NOD/LtSz.Prkdc[scid] and NOD/LtSz.Prkdc[scid].ABHIdd21.1. There were two notable findings from this work. Firstly, NOD.ABHIdd21.1 splenocytes are not as effective as NOD at transferring diabetes to either NOD/LtSz.Prkdc[scid] (P = 0.0004) or NOD/LtSz.Prkdc[scid].ABHIdd21.1 (P = 0.0178), suggesting that Idd21.1 acquired immune cells are not as diabetogenic as NOD. Secondly, NOD/LtSz.Prkdc[scid].ABHIdd21.1 mice are more resistant to autoimmune attack than NOD/LtSz.Prkdc[scid] when injected with either NOD (P = 0.0015) or NOD.ABHIdd21.1 splenocytes (P = 0.0014), suggesting that Idd21.1 either acts by altering the intrinsic resistance of beta-cells to autoimmune attack or due to changes in the innate immune system.
Other NOD-based models of autoimmune disease, spontaneous and experimental autoimmune thyroiditis and spontaneous colitis, were also investigated to determine whether Idd21.1 is a common autoimmune disease locus. When bred onto the NOD.Cg-H2[h4] (thyroiditis model) genetic background Idd21.1 was demonstrated to increase the development of thyroiditis and reduce the incidence of insulitis in spontaneous (untreated) but not experimental (NaI-induced) NOD.Cg-H2[h4] mice. When bred onto the NOD.Cg-Il10[tm1Cgn] (colitis) genetic background Idd21.1 was demonstrated to inhibit the development of rectal prolapse in breeding female NOD.Cg-Il10[tm1Cgn] mice.
Data from this thesis demonstrate that the IDDM6 orthologous region in mouse, Idd21.1, contains several loci that influence autoimmune diabetes, thyroiditis and colitis in NOD-based mouse models. These findings are consistent with previous knowledge that IDDM6 is a common autoimmune susceptibility locus.
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The genetics of abdominal aortic aneurysmsRossaak, Jeremy Ian, n/a January 2004 (has links)
Abdominal Aortic Aneurysms (AAA) are amongst the top ten most common cause of death in those over 55 years of age. The disease is usually asymptomatic, often being diagnosed incidentally. Once diagnosed, elective repair of an AAA results in excellent long-term survival with a 3-5% operative mortality. However, up to one half of patients present with ruptured aneurysms, a complication that carries an 80% mortality in the community, and of those reaching hospital, a 50% mortality. Clearly early diagnosis and treatment results in improved survival.
Screening for AAA, with ultrasound, would detect aneurysms early, prior to rupture. However, debate continues over the cost effectiveness of population based screening programmes. The identification of a sub-population at a higher risk of developing AAA would increase the yield of a screening prograrmne. A number of populations have been examined, none of which have received international acceptance.
About 20% of patients with an AAA have a family history of an aneurysm. The disease is also considered to be a disease of Caucasians, both facts suggesting a strong genetic component to the disease. Perhaps a genetically identified sub-population at a high risk of developing an AAA would prove to be an ideal population for screening.
This thesis examines the incidence of aneurysms and the family histories of patients with AAA in the Otago region of New Zealand. Almost twenty percent of the population has a family history of AAA. DNA was collected from each of these patients for genetic analysis. The population was divided into familial AAA and non-familial AAA for the purpose of genetic analysis and compared to a control population.
AAA is believed to be a disease of Caucasians; a non-Caucasian population with a low incidence of AAA may prove to be a good control population for genetic studies. A literature review demonstrated a higher incidence of AAA in Caucasians than other ethnic groups and within Caucasians a higher incidence in patients of Northern European origin. The incidence was low in Asian communities, even in studies involving of migrant Asian populations. The New Zealand Maori are believed to have originated from South East Asia, therefore could be expected to have a low incidence of AAA and would make an ideal control population for genetic studies. A pilot study was undertaken to examine the incidence of AAA in the New Zealand Maori. The age standardised incidence of AAA proved to be at least equal in Maori to non-Maori, with a more aggressive form of the disease in Maori, manifesting with a younger age at presentation and a higher incidence of ruptured aneurysms at diagnosis.
It is well known that at the time of surgery, an AAA is at the end stage in its life. At this time, inflammation and matrix metalloproteinases (MMP) enzymes are prevalent within the aneurysm wall and have destroyed the wall of the aorta. One of the most important genetic pathways regulating these enzymes is the plasminogen activator inhibiter 1-Tissue plasminogen activator-plasmin pathway.
Genetic analysis of this pathway demonstrated an association of the 4G5G polymorphism in the promoter of the PAl-1 gene with familial AAA. In this insertion:deletion polymorphism, the 5G variant binds an activator and repressor, resulting in reduced PAI-1 expression and ultimately increased MMP activation. This allele was associated with familial aneurysms, 47% versus 62% non-familial AAA and 61% controls (p=0.024).
A polymorphism within the tissue plasminogen activator gene was also examined and no association was found with AAA.
Another way the MMPs expression could be increased is from mutations or polymorphisms in their own genetic structure. Stromelysin 3 is itself a MMP capable of destroying the aortic wall and it has a role in activating other MMPs. A 5A6A insertion:deletion polymorphism exists in the promoter of this gene. The 5A allele variant results in increased stromelysin expression and is associated with AAA 46% versus 33% in controls p=0. 0006.
The actions of the MMPs are themselves inhibited by the tissue inhibitors of matrix metalloproteinases. The TIMP genes have been sequenced; two polymorphisms have been identified in the non-coding promoter area of the TIMP 1 gene. Further studies are necessary to examine the effect of these polymorphisms.
Inflammation has been implicated in aneurysm progression. One of the roles of the inflammatory cells found in an aneurysm is to deliver the MMP�s to the AAA. The HLA system is integral in controlling this inflammation and was therefore examined.
From this series of studies it is concluded that there is a genetic component to AAA. This thesis presents the first genetic polymorphism associated with familial AAA and explores the role of a genetic pathway in the formation of AAA.
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Approaches to identify candidate genes for resistance to facial eczema disease in sheepDuncan, Elizabeth Jenness, n/a January 2007 (has links)
Facial eczema disease (FE) is a secondary photosensitisation disease of ruminants caused by exposure to the mycotoxin sporidesmin. Resistance to FE has a significant genetic component and previous research has included a whole genome scan and investigation of candidate genes. The aim of this study was to use multiple approaches to identify genes associated with resistance to FE.
ABC transporters have been considered as putative candidate genes for FE since the yeast ABC transporter, PDR5, was found to modulate sensitivity to sporidesmin in Saccharomyces cerevisiae. A previous study had shown that hepatic expression of the ovine ABC transporter, ABCB1, was induced following exposure to sporidesmin but only in resistant animals (Longley (1998) PhD Thesis, University of Otago). In the present study, using qRT-PCR, a difference in the expression of ABCB1 between resistant and susceptible animals was not confirmed. It is concluded that ABCB1 is not likely to be a candidate gene for FE.
As the full genome sequences for several mammalian species are now available, phylogenetic analyses were used to identify the most likely mammalian ortholog of the yeast PDR5 protein. This analysis found that the yeast PDR5 protein was most closely related to the mammalian ABCG sub-family. The human ABCG sub-family has five members one of which, ABCG2, is a known xenobiotic transporter. Comparative mapping of ABCG2 indicated that it co-localised to a region of the sheep genome weakly associated with resistance to FE. The full-length sequence of ovine ABCG2 was determined and two synonymous polymorphisms were found. These two polymorphisms, together with an intronic SNP were genotyped across a panel of selection-line animals. The allele frequencies of the intronic SNP were found to be significantly different between the selection lines, providing evidence for the association of ABCG2 with resistance to FE. The hepatic expression of ABCG2 was examined but no differential expression between the selection-lines was observed.
Global gene expression profiling via microarray analysis was undertaken as a novel approach to identify candidate genes. Differences in gene expression were examined between naïve and sporidesmin-dosed resistant and susceptible animals using a bovine cDNA microarray. A small number of differentially expressed genes were identified. Follow-up studies found that there were a relatively high number of errors in EST identity. Eight differentially expressed genes were selected for confirmation by Northern analysis. Six of these genes were shown to be differentially expressed, but neither the patterns nor the magnitude of the differential expression reflected that observed on the microarray. One of the six genes identified as differentially expressed was catalase, which has previously been implicated in resistance to FE. This finding validates the approach taken using gene expression profiling to identify candidate genes.
The final approach used in this study necessitated the development and characterisation of an in vitro system for studying sporidesmin toxicity. The system chosen was a human hepatoma cell line, HepG2. To date the only effective treatment for FE is the prophylactic administration of high levels of zinc sulphate. The mechanism of protection by zinc is unknown, but zinc is known to be a potent modulator of gene expression. Conceptually, any genes modulated by zinc are possible candidates for resistance to FE. It was shown that zinc pre-treatment could protect HepG2 cells against sporidesmin-induced cytotoxicity. Equivalent protection was provided by the addition of zinc in the presence of the transcriptional inhibitor actinomycin D, suggesting that the mechanism of zinc protection is independent of de novo gene transcription.
Overall, the goal of this project was to find genes to assist selection of sheep resistant to FE. Toward this goal, this research has identified several new candidate genes and avenues for investigation.
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Molecular characterisation of chromatin introgressed from Hordeum bulbosum L. into Hordeum vulgare LJohnston, Paul Andrew, n/a January 2008 (has links)
Hordeum bulbosum L. (bulbous barley grass) is an important genetic resource for barley (Hordeum vulgare L.) improvement. As the sole member of the secondary genepool of Hordeum; H. bulbosum represents a relatively untouched source of genetic diversity which can provide novel allelic variation for traits critical to the future of barley breeding. In order to access this resource efficiently, a complete set of molecular marker resources is necessary to assist the introgression of chromatin from H. bulbosum into a barley genetic background.
For breeders to access traits from H. bulbosum for barley improvement, recombinant lines need to be developed to transfer regions of the H. bulbosum genome into a barley background for trait identification and for incorporation into elite barley breeding programs.
The chromosomal location of H. bulbosum introgressions in thirty eight unique recombinant lines was performed using RFLP analysis using mostly distal probes from barley genetic linkage maps However, this analysis was labour intensive, restrictive and prone to inconsistencies due to low intensity signals and complex banding in H. bulbosum.
Due to the low level of interspecific recombination detected between the two species, a retrotransposon-like marker, pSc119.1, was developed which could be used to quickly screen progeny from an interspecific cross to determine which lines possessed introgressions of chromatin from H. bulbosum.
After initial screening, putative recombinants were further characterised using co-dominant single locus PCR markers from throughout the genome. A focus was made on using the EST resources of barley and wheat, combined with the rice genome to create intron-spanning markers. Subsequent allele-sequencing revealed high frequencies of species-diagnostic single nucleotide polymorphisms (SNPs) in the intron regions of these markers, coupled with relatively low frequencies of species-diagnostic SNPs in the flanking exon regions. Overall, interspecific SNP frequencies were not significantly higher in intron-spanning markers than those consisting of exon-only sequence. However, species-diagnostic indels were more frequently discovered within intron sequence providing additional polymorphism.
Recombinant lines with phenotypes that differed from the barley parent allowed those traits to be assigned to particular chromosomal regions. These characterised recombinant lines will provide a resource for barley breeders to identify novel traits for barley improvement and allow identification of new alleles in different chromosomal locations for current traits, allowing greater flexibility for cultivar construction.
A targeted backcross population of the recombinant line 38P18/8/1/10 (possessing leaf rust resistance derived from H. bulbosum) was created. The introgressed region was saturated for PCR markers using a variety of marker types and techniques (AFLP, cDNA-AFLP). Two lines were subsequently identified with introgressions of reduced size relative to the parental recombinant line, both of which have retained the leaf rust resistance trait. The leaf rust resistance was finally linked to two co-dominant EST-based markers located on chromosome 2HL by using these two lines and the direct screening of progeny from interspecific hybrids possessing introgression junctions in the region of interest.
In general, recombinant material between barley and H. bulbosum suffers from certation effects which cause distorted segregation that favours heterozygous and homozygous barley genotypes. Two unique lines have been identified during this research that possess gametocidal-type loci that result in the absolute retention of H. bulbosum chromatin with the termination of gametes lacking the introgression (barley genotype only).
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Genetic contributors to congenital joint dislocationBicknell, Louise Susan, n/a January 2007 (has links)
Understanding the molecular basis of Mendelian disorders featuring joint dislocation can enhance the knowledge of genetic or cellular pathways required in joint development, and provide candidate genes for studying related complex disorders, such as developmental dysplasia of the hip. Two strategies were employed in this project to investigate Mendelian contributors to congenital joint dislocation.
The first strategy was to investigate in-depth a gene known to be associated with joint dislocation. Missense mutations or small in-frame deletions in FLNB, encoding filamin B, have previously been associated with a spectrum of osteochondrodysplasias. Screening a larger cohort established FLNB as the sole underlying disease gene for atelosteogenesis type I and III and also boomerang dysplasia, which was previously thought clinically to be allelic to AOI. Mutations in FLNB cause a large proportion of Larsen syndrome cases with phenotypes reminiscent of the early case series reported. Atypical or "recessive" Larsen syndrome may therefore be due to a different underlying genetic aberration. The disease-associated amino acid substitutions or in-frame deletion/insertions cluster to two main regions of the filamin B protein: the calponin homology 2 domain of the actin-binding domain, and repeats 13-17 of the rod domain. To analyse the functions of these regions, yeast two-hybrid analyses were performed. No interactors were identified with the calponin homology 2 domain, which suggests the amino acid substitutions may disrupt actin binding or the regulation thereof. A candidate interactor, centromere protein J, was identified that binds to repeats 13-15, and could suggest a model for aberrant cell division seen in growth plates of bones of individuals with atelosteogenesis types I and III and boomerang dysplasia.
The second strategy used in this project was to investigate the genetic cause of a novel syndrome featuring joint dislocation. A neurocutaneous phenotype segregated in a consanguineous New Zealand family, and through a genetic mapping strategy, a significantly linked locus was identified at 10q23 (Z = 3.63), in which segregation of a common ancestral haplotype fits the linkage hypothesis of homozygosity by descent. Candidate gene analysis and subsequent screening identified a missense mutation 2350C>T in ALDH18A1, which predicts the substitution H784Y in the encoded protein [Delta]�-pyrroline-5-carboxylate synthase (P5CS). The known function of P5CS in proline and ornithine biosynthesis was not affected by the presence of H784Y in an indirect assay, and therefore the hypothesis proposed was that a novel, unknown moonlighting function of P5CS is perturbed causing the phenotype segregating in the family. As an initial exploration of functions of P5CS in the cell, yeast two-hybrid analysis was undertaken.
This project examined the contribution of two genes, FLNB and ALDH18A1, to Mendelian congenital joint dislocations. How the cellular functions of the encoded proteins in the cytoskeleton, metabolism, or signal transduction, are critical for joint development is ill understood. Future investigations aimed at identifying candidate genes that confer susceptibility to developmental dysplasia of the hip should consider candidate genes that encode proteins related in function to the products of the FLNB and ALDH18A1 genes.
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Genetic studies of morphological variation in the human dentition / Grant Clement Townsend.Townsend, Grant Clement January 1994 (has links)
Includes bibliogrgraphical references. / 1 v. (various pagings) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thirty six journal articles and book chapters aimed at clarifying the roles of genetic and environmental influences on morphological variability within the human dentition. The research falls into three broad categories: Studies of the dentitions of a group of Australian aborigines; Studies of the dentitions of individuals with chromosomal abnormalities; Studies of the dentitions of twins. The results of research carried out over approximately a ten year period. / Thesis (D.D.Sc)--University of Adelaide, Dept. of Dentistry, 1995?
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Genotypic variation for manganese efficiency in cereals / Nico Emile MarcarMarcar, Nico Emile January 1986 (has links)
Includes bibliographies / 201 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agronomy, 1987
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Studies on the 5-aminolevulinate synthase gene and its regulation / Deborah Jane MaguireMaguire, Deborah Jane January 1987 (has links)
Includes bibliography / 100 leaves, [8] leaves of plates : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Biochemistry, 1987
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