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Negative Regulation of Cell Fate Specification by the lin-15 Locus During Vulval Induction in Caenorhabditis elegans


Gonzalez-Serricchio, Aidyl Sofia (2000) Negative Regulation of Cell Fate Specification by the lin-15 Locus During Vulval Induction in Caenorhabditis elegans. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/ppq9-ps50.


We have visualized extrachromosomal arrays by targeting the green fluorescent protein (GFP) to a specific DNA sequence (lac operator) incorporated into Caenorhabditis elegans' transgenes. This system can be used to determine polyploidy and to investigate chromosome segregation. This technique also allows rapid, accurate determination of spontaneous loss of an array, thereby allowing high-resolution mosaic analysis. We carried out genetic mosaic analysis on lin-3 (epidermal growth factor) using the GFP-Lacl + lacO method. This methodology confirmed lin-3's site of action for vulval induction is at the anchor cell. This result also proved this technique works.

We used both the GFP-Lacl + lacO256 system as well as the ncl-1 gene as genetic mosaic markers to determine the site of action of lin-15A and lin-15B. Both markers indicate that lin-15A gene function is required within the vulval precursor cells (VPCs) to prevent an excessive number of VPCs from generating vulval progeny. The mosaic expression pattern for lin-15B is broad therefore, proven difficult to pinpoint a site of action.

The products of the lin-15 gene were first defined genetically as negative regulators of the vulval induction pathway. It encodes two novel hydrophilic proteins, LIN-15A and LIN-15B. According to antibody stainings and GFP expression patterns, both proteins are nuclear and present in almost all the cells. lin-15 is part of the synthetic multivulva (synMuv) set of genes which are comprised of two classes, A and B. Mutation of both an A and a B gene is required to obtain a multivulva (Muv) phenotype. Further characterization of the lin-15 locus reveals an effect on fertility.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Biology; Genetics
Degree Grantor:California Institute of Technology
Major Option:Biology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Sternberg, Paul W.
Thesis Committee:
  • Sternberg, Paul W. (chair)
  • Zinn, Kai George
  • Meyerowitz, Elliot M.
  • Hay, Bruce A.
  • Lester, Henry A.
Defense Date:17 May 2000
Non-Caltech Author Email:aidylsofia (AT)
Record Number:CaltechTHESIS:07022021-160304976
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14292
Deposited By: Benjamin Perez
Deposited On:02 Jul 2021 16:48
Last Modified:06 Aug 2021 18:57

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