High impact information on lin-26

• A tissue-specific knock-out strategy reveals that lin-26 is required for the formation of the somatic gonad epithelium in Caenorhabditis elegans [1].
• In this way, we rescued the lethal phenotype imparted by lin-26 null mutations and uncovered a highly penetrant sterile phenotype [1].
• Specifically, the strongest of these new alleles was characterized by the absence of lin-26 expression in the somatic gonad, the presence of endomitotic oocytes, decreased germline proliferation, a protruding vulva and a less penetrant absence of gonad arms [1].
• The C. elegans gene lin-26, which encodes a presumptive zinc-finger transcription factor, is required for hypodermal cells to acquire their proper fates [2].
• The CDC42Ce cDNA maps to a position on C. elegans chromosome II in close proximity to lin-26, a cell lineage gene [3].

Biological context of lin-26

• lir-2, lir-1 and lin-26 encode a new class of zinc-finger proteins and are organized in two overlapping operons both in Caenorhabditis elegans and in Caenorhabditis briggsae [4].
• The second operon, which is expressed in the nonneuronal ectoderm, includes short lir-1 isoforms, starting at exon 2 and lin-26 [4].
• We show that the lir-1(RNAi) phenotypes resulted from a severe loss of lin-26 gene expression [5].
• Our characterization indicates that (1) pvl-4 and pvl-5 are required for generation/survival of the VPCs; (2) bar-1, mom-3/mig-14, egl-18, and sem-4 play a role in VPC fate specification; (3) lin-26 is required for proper VPC fate execution; and (4) pvl-6 acts during vulval morphogenesis [6].

Anatomical context of lin-26

• Structural conservation is functionally meaningful as C. briggsae lin-26 is also expressed in the nonneuronal ectoderm and can complement a C. elegans lin-26 null mutation [4].
• We have previously shown that the putative C2H2 zinc-finger transcription factor LIN-26 is required for the differentiation of ectodermal and mesodermal epithelial cells in Caenorhabditis elegans [7].
• Here we show that lin-26 is expressed until the somatic gonad primordium stage in all cells of the somatic gonad, except in distal tip cells, and later in all uterine cells [1].
• We also show that lin-26 promoter elements mediate activation in the epidermis (hypodermis) by the GATA factor ELT-1, or repression in the foregut (pharynx) by the FoxA protein PHA-4 [8].

Other interactions of lin-26

• In contrast, lin-26 function does not appear necessary for elt-3 expression [9].
• In addition, on the basis of their Pvl phenotypes, we show that the previously identified genes lin-26, mom-3/mig-14, egl-18, and sem-4 also function during vulval development [6].

Analytical, diagnostic and therapeutic context of lin-26

• Using GFP reporters and mutant rescue assays, we performed a molecular dissection of the lin-26 promoter and could identify almost all elements required to establish its complex spatial and temporal expression [8].

References