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|Title:||Molecular genetic study of vulval morphogenesis in C. elegans and related nematode species|
|Keywords:||Molecular;genetic study;vulval morphogenesis;C. elegans;nematode species|
|Abstract:||<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>|
|Appears in Collections:||Digitized Open Access Dissertations and Theses|
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