The homeodomain protein PAL-1 specifies a lineage-specific regulatory network in theC. elegansembryo

Abstract

analysis demonstrates that the identified PAL-1 target genes affect specification, differentiation and morphogenesis of C-lineage cells. In particular, we show that cell fate-specific genes (or tissue identity genes) and a posterior HOX gene are activated in lineage-specific fashion. Transcription of targets is initiated in four temporal phases, which together with their spatial expression patterns leads to a model of the regulatory network specified by PAL-1.

Automated cell lineage tracing in Caenorhabditis elegans

“…Microarray and serial analysis of gene expression data combined with homeotic mutants (12,13), RNA enrichment methods (14), or FACS sorting of individual cells (15) reveal active genes within particular cells or stages of development. In situ hybridization (16) can localize mRNAs to particular stages and tissues.…”

MyoD, modularity, and myogenesis: conservation of regulators and redundancy in C. elegans: Figure 1.

“…lineages into muscle by PAL-1 activity, hlh-1 expression is positively regulated by PAL-1 (Baugh et al 2005a;Fukushige and Krause 2005). Baugh et al (2005a) identified hlh-1 in a microarray analysis of mRNA expression aimed at identifying PAL-1 transcriptional regulatory targets using mutant embryos with either no [pie-1 −/− ; pal-1(RNAi)] or excess PAL-1 activity [mex-3 −/− ; skn-1(RNAi)], and in the same experiment unc-120 and hnd-1 were also identified.…”

“…Baugh et al (2005a) identified hlh-1 in a microarray analysis of mRNA expression aimed at identifying PAL-1 transcriptional regulatory targets using mutant embryos with either no [pie-1 −/− ; pal-1(RNAi)] or excess PAL-1 activity [mex-3 −/− ; skn-1(RNAi)], and in the same experiment unc-120 and hnd-1 were also identified. Using reporter gene analysis and RNAi of pal-1 and its repressor mex-3; hlh-1, unc-120, and hnd-1 were each shown to be expressed in early embryonic myoblasts under the control of PAL-1 (Baugh et al 2005a).…”

“…Baugh et al (2005a) identified hlh-1 in a microarray analysis of mRNA expression aimed at identifying PAL-1 transcriptional regulatory targets using mutant embryos with either no [pie-1 −/− ; pal-1(RNAi)] or excess PAL-1 activity [mex-3 −/− ; skn-1(RNAi)], and in the same experiment unc-120 and hnd-1 were also identified. Using reporter gene analysis and RNAi of pal-1 and its repressor mex-3; hlh-1, unc-120, and hnd-1 were each shown to be expressed in early embryonic myoblasts under the control of PAL-1 (Baugh et al 2005a). The overlapping temporal and spatial expression patterns, common upstream regulation, and similar mutant phenotypes of hlh-1 and unc-120 (Caldicott and Waterston 1991;Chen et al 1992Chen et al , 1994Williams and Waterston 1994) led to the suggestion that hlh-1, unc-120, and hnd-1 function together to control muscle specification (Baugh et al 2005a).…”

“…Using reporter gene analysis and RNAi of pal-1 and its repressor mex-3; hlh-1, unc-120, and hnd-1 were each shown to be expressed in early embryonic myoblasts under the control of PAL-1 (Baugh et al 2005a). The overlapping temporal and spatial expression patterns, common upstream regulation, and similar mutant phenotypes of hlh-1 and unc-120 (Caldicott and Waterston 1991;Chen et al 1992Chen et al , 1994Williams and Waterston 1994) led to the suggestion that hlh-1, unc-120, and hnd-1 function together to control muscle specification (Baugh et al 2005a). In a subsequent study, synthetic lethality was systematically investigated for all pairs of validated PAL-1 targets in an effort to discover functions that are hidden from normal genetic screens by functional redundancy (Baugh et al 2005b).…”