Multiple HOM-C gene interactions specify cell fates in the nematode central nervous system.
Intricate patterns of overlapping HOM-C gene expression along the A/P axis have been observed in many organisms; however, the significance of these patterns in establishing the ultimate fates of individual cells is not well understood. We have examined the expression of the Caenorhabditis elegans Antennapedia homolog mab-5 and its role in specifying cell fates in the posterior of the ventral nerve cord. We find that the pattern of fates specified by mab-5 not only depends on mab-5 expression but also on post-translational interactions with the neighboring HOM-C gene lin-39 and a second, inferred gene activity. Where mab-5 expression overlaps with lin-39 activity, they can interact in two different ways depending on the cell type: They can either effectively neutralize one another where they are both expressed or lin-39 can predominate over mab-5. As observed for Antennapedia in Drosophila, expression of mab-5 itself is repressed by the next most posterior HOM-C gene, egl-5. Thus, a surprising diversity in HOM-C regulatory mechanisms exists within a small set of cells even in a simple organism.
Salser
S J
SJ
Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0554.
Loer
C M
CM
Kenyon
C
C
D000818:Animals; D017209:Apoptosis; D017173:Caenorhabditis elegans / Q000166:cytology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002459:Cell Fusion; D002490:Central Nervous System / Q000166:cytology*; D000078404:Epidermal Cells; D015870:Gene Expression; D005801:Genes, Homeobox; D015801:Helminth Proteins / Q000235:genetics*; D018398:Homeodomain Proteins; D014157:Transcription Factors / Q000235:genetics*
D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D018398:Homeodomain Proteins; C081538:Mab-5 protein, C elegans; D014157:Transcription Factors