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POP-1/CETCF-1 has multiple functions in P ectoblast development

Deshpande, Rashmi Jayant
http://rave.ohiolink.edu/etdc/view?acc_num=osu1133378295

Abstract Details

2005, Doctor of Philosophy, Ohio State University, Molecular Genetics.
Wnt pathways are highly conserved pathways that regulate key processes such as cell type specification and migration of cells during animal development. The C. elegans vulva displays symmetry such that the posterior half of the vulva forms a mirror image of the anterior half. We observed that nuclear levels of POP-1 also display similar mirror symmetry in the developing vulva. We are studying the processes that establish this mirror symmetric pattern of POP-1 localization. Because mutations in the putative WNT receptors lin-17/frizzled and lin-18/Ryk were known to cause defects in the posterior half of the vulva, we examined POP-1 localization patterns in these mutants. We observed that POP-1 localization is reversed in the posterior most part of the vulva with respect to wild-type, in these mutants. lin-17/lin-18 double mutants show a more penetrant reversal of POP-1 localization, suggesting that LIN-17 and LIN-18 act in a semi-redundant manner to reorient POP-1 localization in the posterior half of the vulva. We have investigated the mechanisms by which two other P ectoblasts, P11 and P12 are specified. Prior studies have shown that lin-44/Wnt, lin-17/Frizzled and bar-1/canonical b-catenin function in P12 specification. We have obtained additional evidence that a canonical Wnt pathway functions in P12 specification. We have demonstrated that activated forms of BAR-1 (deltaNBAR-1) are sufficient to cause a P11 to P12 transformation. Interestingly, time-course studies with deltaNBAR-1 expression suggest that Wnts may act at the same time as the EGF pathway, suggesting the requirement of two parallel pathways. We predict a function for POP-1 in P12 specification as BAR-1 and b-catenins in other organisms are known to act primarily through TCFs to activate transcription. We found that the pop-1 hypomorphs, hu9 and q645 that should reduce bar-1 activity cause a low rate of P12 to P11 transformations. This supports the hypothesis that POP-1 acts in P12 specification in a BAR-1 dependent manner. Surprisingly, we find that pop-1 RNAi causes a P11 to P12 transformation, revealing a second function of POP-1 in P11 specification. This antagonistic function of POP-1 appears to be independent of BAR-1 as observed by epistasis experiments. We find that multiple Wnts act in P12 specification. lin-44(n1792/Wnt) and egl-20(n585)/Wnt double mutants display an enhanced rate of P12 to P11 transformations. Genetic analysis using other Wnts and Wnt receptors possibly functioning with LIN-44 and LIN-17 in P12 specification will be discussed.
Russell Hill (Advisor)
216 p.
Biology, Cell
Wnt signaling; canonical; non-canonical mechanisms; POP-1; P ectoblasts

Recommended Citations

Citations

  • Deshpande, R. J. (2005). POP-1/CETCF-1 has multiple functions in P ectoblast development [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1133378295

    APA Style (7th edition)

  • Deshpande, Rashmi. POP-1/CETCF-1 has multiple functions in P ectoblast development. 2005. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1133378295.

    MLA Style (8th edition)

  • Deshpande, Rashmi. "POP-1/CETCF-1 has multiple functions in P ectoblast development." Doctoral dissertation, Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1133378295

    Chicago Manual of Style (17th edition)

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© 2005, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.