High impact information on pal-1

• We find that pal-1 activity is sequentially restricted to this blastomere [1].
• We propose that the segregation of PIE-1, combined with the temporal decay of SKN-1, targets pal-1 activity to this posterior lineage, thus coupling the regulation of this conserved posterior patterning gene to asymmetric cell cleavages [1].
• The activities of cell signals and pal-1 appear to influence V cell fates by determining the state of a developmental switch that involves two homeotic genes, lin-22 and mab-5 [2].
• These cell interactions are inhibited in specific posterior V cells by the activity of the gene pal-1, which allows these cells to generate rays instead of alae [2].
• The pal-1+ protein could block the response to cell signals either by repressing genes involved in signal transduction or by acting directly on downstream genes in a way that neutralizes the effects of the intercellular signals [3].

Biological context of pal-1

• To examine the mutagenic spectrum of 4,5',8-trimethylpsoralen (TMP) in Caenorhabditis elegans, we isolated mutations in the unc-22 and pal-1 genes following TMP mutagenesis and analyzed them for restriction fragment length polymorphisms by Southern blot [4].
• First, the caudal homolog pal-1 turns on mab-5 in V6 during embryogenesis [5].
• To evaluate the amount of synteny between the two genomes, we have obtained 126 kb of continuous genomic sequence of P.pacificus, flanking the developmental patterning gene pal-1 [6].

Anatomical context of pal-1

• While pal-1 mRNA is present throughout the oocyte and early embryo, PAL-1 protein is expressed only in posterior blastomeres, starting at the four-cell stage [7].
• Aberrant early cell positions are observed in posterior hypodermis, both in the C-lineage cells that express pal-1 and in the neighboring hypodermal seam cell precursors, which do not, as well as in posterior muscle derived from the C and D lineages [8].

Regulatory relationships of pal-1

• In sop-1 mutants, pal-1 is activated by a pathway that is stimulated by bar-1/beta-catenin, a component of the Wnt signal transduction pathway [9].

Other interactions of pal-1

• Signaling between V cells is required for the formation of the neuroblast; however, which of the V cells can make a postdeirid is not determined by these signals but rather by the action of the homeotic lin-22 and pal-1 genes [10].
• Furthermore, pal-1, a caudal homologue with maternal product necessary for the proper development of the C blastomere, is both necessary and sufficient for vab-7 expression [11].

References