Novak, Preston et al. (2015) International Worm Meeting "Splicing machinery potentiates post-transcriptional regulation of germline development."

Ellenbecker, Mary, Feilzer, Sara, Wang, Xiaobo, Novak, Preston, Voronina, Ekaterina

[International Worm Meeting, 2015]

Germline stem cell proliferation in C. elegans is controlled in a large part by the FBF genes (fbf-1 and fbf-2; Crittenden et al., 2002). In the course of searching for FBF cofactors, we found that components of splicing machinery may contribute to FBF activity. Individual knockdowns of several splicing factors caused enhanced sterility of fbf-1 and fbf-2 single mutants compared to the wild type worms. This sterility was associated with masculinization of germline, a phenotype associated with disruption of FBF function. We further found that knockdown of these splicing factors caused misexpression of a transgenic reporter controlled by fog-1 3'UTR, which is normally repressed in stem cells by FBFs. Next, we tested whether splicing factors influence other post-transcriptional regulation in germline in addition to their contribution to FBF function or oogenesis. We find that splicing factor knockdown is also able to enhance defects in spermatogenesis caused by the temperature-sensitive mutation in fog-1, arguing that functional splicing cascade influences multiple post-transcriptional processes. Finally, we found that splicing factor knockdown does not worsen embryonic lethality caused by a mutation unrelated to post-transcriptional regulation (dhc-1ts). In all these assays, we think that knockdown of splicing factors decreased the efficiency of RNA processing, but did not completely eliminate it.We conclude that inefficient pre-mRNA splicing may interfere with multiple post-transcriptional regulatory events, which has to be taken into account when conducting genetic interaction screens.

Sara Vassalli et al. (2006) European Worm Meeting "Identification of Genes required for Anchor Cell Attachment and Invasion during Vulval Development"

ALEX HAJNAL, Sara Vassalli

[European Worm Meeting, 2006]

Sara Vassalli and Alex Hajnal. During vulval development in the hermaphrodite, three out of six equivalent vulval precursor cells (the VPCs P3.p to P8.p) are induced by a signal from the gonadal anchor cell (AC). The LIN-3 EGF growth factor produced by the AC activates the EGFR/RAS/MAPK pathway in the VPCs to specify the primary cell fate. Prior to vulval induction, the gonad is separated from the VPCs by two basal laminas covering each tissue such that the position of the AC relative to the VPCs is variable when the animal moves. At the time of vulval induction in the early L3 stage, however, the AC attaches to the basal side of the future primary cell P6.p. After the first round of vulval cell divisions (Pn.px stage), the basal laminas separating the gonad from the vulval cells start to dissolve precisely under the AC. After the second round of divisions (Pn.pxx stage), the basal laminas between the AC and the four primary vulval cells are interrupted, and the AC invades the vulval tissue.. While the mechanism of vulval induction is well studied, less is known about genes regulating the attachment of the AC to P6.p and the following invasion step. To study these two processes, we performed a forward genetic screen for mutants with defects in AC positioning and/or invasion. Since worms with an abnormal or missing connection between the gonad and the vulva usually display a protruding vulva (Pvl) phenotype, we first screened for animals with a Pvl phenotype and then examined them for defects in the positioning or invasion of the AC. Among 5300 F1 clones, we identified 8 sterile mutants with a misplaced AC and 2 mutants, in which the AC is normally positioned but fails to dissolve the basal laminas and invade the vulval tissue. Details about the cloning and analysis of the genes identified in this screen will be presented at the meeting.