Spelling suggestions: "subject:"vulvar morphogenesis""
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The Role of Class I Histone Deacetylase HDA-1 in vulval morphogenesis in NematodesJoshi, Katyayani 09 1900 (has links)
Histone deacetylases (HDACs) are an ancient class of enzymes that have
been conserved throughout evolution and are found in diverse organisms such as
animals, plants, fungi, eubacteria and archaebacteria. In C. elegans, twelve
HDACs have been identified so far. These HDACs have been grouped into four
different classes (Class I, II, III and IV) based on their cofactor requirements and
sequence homologies. hda-1 is one of the three Class I HDACs in C. elegans and
plays a role in the morphogenesis of several organs including the vulva. This thesis focuses on the role of hda-1 in vulval morphogenesis. The hermaphrodite vulva has twenty-two cells which can be further divided into seven different cell types: VulAs, VulBls, VulB2s, VulCs and VulDs (secondary great granddaughters), YulEs and VulFs (primary great granddaughters). The analysis of expression pattern of hda-1 revealed that hda-1 is expressed in the progeny of
both the primary and secondary vulval precursor cells (VPCs). To examine hda-1 mutant phenotype in detail, I examined the expression pattern of five different vulval cell-type specific markers (cdh-3, zmp-1, ceh-2, egl-17 and daf-6) in hda-1 animals. The results revealed that hda-1 is necessary for proper differentiation of multiple vulval cell types. To study the evolutionary conservation of hda-1 function, I examined the role of hda-1 ortholog in C. briggsae. C. briggsae is a close relative of C. elegans and has almost identical vulval morphology. Knocking down Cbr-hda-1 in C. briggsae animals resulted in defective vulval phenotype. Consistent with this
result, the expression of two cell- fate specific markers (C. briggsae orthologs of zmp-1 and egl-17) was found to be altered in Cbr-hda-1 RNAi treated animals. Thus, hda-1 function in the vulva appears to be conserved in these two species. To identify the hda-1 targets in vulval morphogenesis in C. elegans, microarray approach was taken. Two genes fos-1 and lin-29 were identified as putative targets and were examined in some detail. Among the targets identified
(these still need to be validated), I focused on fos-1 and lin-29 for detailed
investigation. The RNAi-mediated knockdown of hda-1 caused alterations in the
expression pattern ofthefos-1 transcript,fos-1b. To examine interaction between
fos-1 and lin-29, I used double RNAi approach and examinedfos-1 (RNAi), lin-
29 (RNAi), hda-1 (cw2) animals. It was found that fewer animals exhibit defects
in vulval morphology in these animals as compared to fos-1 (RNAi), hda-1 (cw2)
animals. While this suggests a possible interaction between lin-29 and hda-1 in
the vulva, these results need to be validated by doing additional experiments. In summary, the work described in this thesis demonstrates that hda-1 plays an important role in vulval morphogenesis and regulates the expression of several important genes. Also, the function of hda-1 in C. elegans and C. briggsae
is evolutionarily conserved. / Thesis / Master of Science (MSc)
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Molecular genetic study of vulval morphogenesis in C. elegans and related nematode speciesPanyala, Sujatha 29 June 2017 (has links)
<p> Caenorhabditis elegans (C. elegans) is a model organism which is known for its
transparent body, small body size, high reproductivity and short lifecycle. Several
important genes and signal transduction pathways are well conserved in C. elegans. lin//,
a LIM homeobox family member, plays a crucial role in the development of the
vulva in C. elegans. LIM homeobox genes are a subgroup of Homeobox family that play
fundemental role in animal development. In C. elegans lin-If mutant animals fail to form
a functional vulva and vulval-uterine connection and consequently exhibit egg-laying
defective phenotype. The cell lineage and marker gene expression studies have shown
that lin-// is required for the patterning of all primary and secondary lineage vulval cells.
lin- II also functions in the nervous system. </p> <p> lin-// expression is mainly observed in the developing vulval cells and in the pi cells which are involved in the formation of vulval-uterine connection. lin-If expression is
also seen in VCs and in some of the head and tail neurons. The completed genome
sequences of closely related species in Caenorhabditis genus serve as a power tool to do
systematic comparative studies. The lin-If regulatory sequences from these species have
been compared along with the expression patterns. </p> <p> We looked at the regulation of lin-// in closely related nematode species like C. elegans, C. briggsae, C. remanei and Caenorhabditis n species. </p> <p> Consistent with this. expression of lin-11 is observed in the developing vulval cells. We are interested in understanding evolutionary changes in the regulation and function of lin-II in reproductive system </p> <p> /in-11 is a LIM homeodomain family member which IS involved in several developmental events. lin-11 role is documented in the thermoregulatory circuit
specifying AIY interneuron, in chemosensory neurons like A W A and olfactory neurons
A WS. During vulval development lin-II expression is dynamically expressed in subset
of secondary lineage cells and is broadly expressed in all the cells indicating its role in
cell identity and cell fusion of the vulval cells. lin-II is also required for the formation of
vulval uterine connection which is the passage to lay eggs in the hermaphrodite. linllloss
of function hermaphrodites have change in the axis of the secondary lineage cells
during vulval development, uterine Jt cell migration defect, defects in the AIY, A W A and
A WS interneurons resulting in egg-laying defect and protruding vulva and neuronal
defects and reduced mating efficiency. </p> <p> The expression pattern of lin-If in closely related species is highly similar but not identical. From the sequence comparison of lin-If regulatory sequences a 1 kb conserved
block of sequences have been identified which includes the regulatory sequences
responsible for the expression of lin-If in vulva and Jt cells. We propose that cisregulatory
elements controlling lin-If gene expression are slowly evolving though there
is no change in the function which indicates that lin-If plays critical role during the
development of the vulva and other tissues. </p> / Thesis / Master of Science (MSc)
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