1. The DNA sequence of the human complement C4A gene from a cosmid clone Cos 3A3 was determined and the complete exon-intron structure elucidated. The 5' flanking region of the C4 gene contains three TATA sequences and a transcriptional enhancer core sequence, which are >200 nucleotides (nt) and 60-70 nt upstream from the CAP site, respectively. The gene consists of 42 exons coding for a precursor protein of 1745 residues. The first exon codes for a 51 nt 5' untranslated sequence, a leader peptide of 19 residues, and the N-terminus of the β chain. The β-α and the α-γ chain junctions are encoded by exons 17 and 34, respectively. The anaphylatoxin C4a and the thiolester site are encoded by phase 1-1 symmetrical exons. Most of the amino acids encoded at the splice junctions are polar or charged. Between exons 10 and 11 is a 6-7 kb intron that is flanked by direct long terminal repeats and may be absent in some C4 genes located at the second C4 locus. The last exon codes for the C-terminus of the γ chain and a 140 bp 3' untranslated sequence. The intergenic region between the C4 gene and its neighbouring 21-hydroxylase (210Hase) gene is ~3028 bp. 2. Eighteen polymorphic amino acids on C4 have been identified through genomic DNA, cDNA and protein sequencing. Fourteen of them are located on the* chain (C4a: 2 changes; C4d: 12 changes). The rest are scattered on the β and the γ chains. There are potential size variations by one residue on the β chain, and by a tripeptide that contains a sulphation site on the α chain. 3. Four common and rare C4 alleles have been cloned from individuals whose C4 proteins were chemically and serologically characterised. Analysis of the sequences at the C4d regions has allowed the identification of the C4A/C4B isotypic residues at positions 1101-6: C4A has the sequence PCPVLD, while C4B has the sequence LSPVIH. Presumably these isotypic residues are the cause of the class-specific, differential chemical reactivates. Moreover, the probable locations for the two Eodgers (Kg) and the six Chido (Ch) antigenic determinants were deduced. The C4B isotypic residues may be involved in the expression of the Ch2 and the Ch4 epitopes, while the C4A isotypic residues may not be related to either of the Eg determinants. 4. Definitive restriction fragment length polymorphisms (RFLPs) representing the exact locations responsible for the isotypicity between C4A and C4B, and for their generally associated Rg1 and Ch1 antigenic determinants, have been designed. In combination with the Taq I polymorphic patterns specific for the C4 and for the 210Hase gene loci, it has been shown that the null allele of the HLA haplotype B44 DR6 C4A 3 C4B QO is not a C4B allele, but probably encodes another C4A 3 allotype at the second C4 locus.

A genetic approach to lowering protease (plasmin) levels in milk, requires the presence of polymorphism of bovine plasminogen. This study was conducted to determine to what extent genetic polymorphism exists in dairy cattle. Bovine plasminogen was first purified from Holstein cow plasma by affinity chromatography on Lysine-Sepharose and antibodies to bovine plasminogen were raised by monthly intramuscular injection of the isolated bovine plasminogen into rabbits. For plasminogen phenotyping, blood samples were collected at random from 50 Holstein and Ayrshire cattle, and plasminogen was isolated from the plasma using lysine-Sepharose and then treated with neuraminidase. After separation by isoelectric focusing (pH 3.5-9.5) in polyacrylamide gels, Plasminogen polymorphs were detected immunologically using rabbit anti-bovine plasminogen antibodies. Additionally, the plasminogen isoforms were evaluated with a functional assay (caseinolytic overlay technique) after activation of the plasminogen with urokinase. Six plasminogen phenotypes were identified which represent products of 5 variant alleles. The 5 plasminogen variants were characterized based on their isoelectric points and designated PLG A$ sb2$ (pI 6.5 and 7.0), B$ sb2$ (pI 7.6 and 7.8), C$ sb1$ (pI 6.8), D$ sb2$ (pI 7.8 and 8.0), and E$ sb2$ (pI 6.8 and 7.0). PLG A$ sb2$ and PLG B$ sb2$ were the most common variants in these cattle. The 6 phenotypes were $ rm A sb2A sb2, B sb2B sb2, A sb2B sb2, B sb2C sb1, A sb2D sb2 and D sb2E sb2$. The phenotypic frequencies in Holstein and Ayrshire were very different, $ rm A sb2A sb2 and B sb2B sb2$ being respectively the most frequent phenotype. In addition, DNA polymorphism at bovine plasminogen gene was detected when genomic DNA was digested with the restriction enzyme Msp I and hybridized with mouse plasminogen cDNA. This is the first description of plasminogen polymorphism reported in dairy cattle. If different variants have altered activity, the detrimental effect

No description available.

No description available.

ABSTRACT Background Cutaneous melanoma is a potentially lethal cancer for which incidence rates have risen dramatically in white-skinned populations worldwide over the past decades. While some risk factors for melanoma have been clearly established, such as pigmentary characteristics, sun exposure, and familial history of the disease, emerging evidence suggests that other factors, such as hormonal and genetic factors, may play a role in the aetiology of this cancer. The present work aimed at 1) examining the relationships between hormonal factors, benign gynaecological conditions, and the risk of melanoma, and 2) to explore shared risk factors for endometriosis and melanoma in a large French prospective cohort; and 3) to study the potential associations between novel naevus-associated gene variants and the risk of melanoma in a large Australian population-based study. Methods The E3N prospective cohort includes 98,995 French women insured by a national scheme mostly covering teachers, and aged 40-65 years at inclusion. Women were followed-up approximately every two years starting in 1990 through self-administered questionnaires. A first investigation focused on the potential association between a personal history of endometriosis or of other benign gynaecological conditions and the risk of melanoma, which was examined in the E3N cohort using Cox proportional hazards regression models. A second study explored the potential relationships between cutaneous phenotypic factors associated with melanoma and the risk of endometriosis in the E3N cohort, using unconditional logistic regression models. A third investigation used data from the Q-MEGA (an Australian study that followed-up four population-based samples of melanoma patients in Queensland, diagnosed between 1987 and 1995), as well as from the BTNS (a study including adolescent twins and their parents), from which the parents of the twins served as healthy controls in the present investigation. The association between novel naevus-associated gene variants and the site- and subtype-specific risk of melanoma was assessed using unconditional multinomial logistic regression models. Results A significantly positive association was observed between a personal history of endometriosis and the risk of melanoma in the E3N cohort, as well as a significantly positive association between a personal history of uterine fibroma and melanoma risk. The association between endometriosis and melanoma was even stronger when restricting to endometriosis reported as treated or diagnosed by laparoscopic surgery. However, a history of ovarian cyst, uterine polyp, breast adenoma/fibro-adenoma or breast fibrocystic disease was not significantly associated with the risk of melanoma. Also, significantly positive dose-effect relationships were found in the E3N cohort between the risk of endometriosis and skin sensitivity to sun exposure, number of naevi, and number of freckles, while no significant associations were found with hair or skin colour. Finally, variants of MTAP, PLA2G6 and IRF4 were significantly associated with the propensity to develop naevi in the Q-MEGA study. There was also a statistically significant association between MTAP rs10757257 and the risk of melanoma. Although there was no evidence that this association varied according to anatomical site of the tumour, the risk alleles of this polymorphism were more common in patients with superficial spreading melanoma or nodular melanoma than in controls, while patients with melanoma of the lentigo maligna type were no more likely than controls to carry these alleles. In contrast, no association was found between PLA2G6 and IRF4 variants and the risk of melanoma, globally or by site or type of melanoma. Conclusion The present findings suggest a positive association between endometriosis and melanoma, for which they constitute the strongest evidence to date. This finding may reflect the existence of shared risk factors between endometriosis and melanoma, which is supported by the finding of significant associations between endometriosis and some cutaneous phenotypic traits that are established risk factors for melanoma. Because these traits are mostly genetically determined, it can be speculated that endometriosis and melanoma share similar genetic characteristics. More research will be needed in order to clarify common pathways between endometriosis and melanoma. The finding of a positive association between uterine fibroma and melanoma risk had not been previously reported and warrants further investigation. The presented results also confirm an association between MTAP, PLA2G6 and IRF4 variants and naevus propensity, as well as an association between MTAP and melanoma. The findings suggest that the relationship is subtype-specific, which confirms and further refines the overarching “divergent pathways” model. Since MTAP is located at the same locus as CDKN2A, which has also been associated with naevus counts, further research will be necessary to determine whether these results can be attributed to MTAP independently of CDKN2A.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.

Thesis (Ph. D.)--University of Adelaide, 1968. / Includes bibliographical references.

Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available online.

Thesis (M. Phil.)--University of Hong Kong, 2008.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [92]-104).