Development of a multicellular organism requires precise coordination of temporal and spatial cues to ensure that developmental events occur at the correct time and place. C. elegans vulval development offers a convenient experimental system for investigating the temporal and spatial regulation of multiple developmental decisions in response to different patterning signals. In this thesis, I present my studies on the temporal control of Vulval Precursor Cell (VPC) fate patterning through analyses of VPC development defects in heterochronic mutants. I show that loss of the miRNA lin-4 inhibits LIN-12/Notch activity through persistence of LIN-14, but not LIN-28 or HBL-1. Persistent lin-14 blocks LIN-12 activity without interfering with the key events of LIN-12/Notch signal transduction, and lin-14 activity in the second larval stage is sufficient to prevent premature LIN-12 activation. I also present evidence that persistent lin-14 activity impedes extension of the VPC apical domains, and that ectopic Wnt signaling prevents the daughters of uninduced VPCs from fusing with the major hypodermal syncytium in lin-4 null mutants. Finally, through characterization of heterochronic mutants that exhibit precocious or delayed vulval induction, I provide clues to possible mechanisms underlying the temporal control of vulval induction.
Identifer | oai:union.ndltd.org:columbia.edu/oai:academiccommons.columbia.edu:10.7916/D81J9HQW |
Date | January 2011 |
Creators | Li, Ji |
Source Sets | Columbia University |
Language | English |
Detected Language | English |
Type | Theses |
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