Lineage-specific regulators couple cell lineage asymmetry to the transcription of the Caenorhabditis elegans POU gene unc-86 during neurogenesis.
The POU homeo box gene unc-86 specifies neuroblast and neural identities in the developing Caenorhabditis elegans nervous system. After an asymmetric neuroblast division, unc-86 is expressed in one of two daughter cells in 27 lineage classes that are not obviously related by function or position. We show here that unc-86 transcriptional regulatory regions detect cell lineage asymmetry to activate unc-86 expression in one of two neuroblast daughter cells. Distinct regulatory regions activate unc-86 expression in particular sets of sublineages. Therefore the unc-86 regulatory region integrates distinct cell lineage asymmetry cues to activate unc-86 expression in the many classes of neuroblast cell lineages. In agreement with such lineage-specific regulation of unc-86 asymmetric activation, mutations in lin-11 (LIM homeo box), ham-1, and lin-17 affect the asymmetry of unc-86 expression in particular cell lineages, and mutations in lin-32 (achaete/scute family), vab-3 (Pax-6 homolog) and egl-5 (Abd-B homolog) affect the establishment of unc-86 expression in other cell lineages. Homologs of unc-86 and many of these unc-86 regulators have been implicated in control of neurogenesis in vertebrates and invertebrates. These data suggest that unc-86 acts in a phylogenetically conserved pathway that couples neuroblast cell lineage asymmetry to the generation of diverse neural types.
Baumeister
R
R
Department of Molecular Biology, Massachusetts General Hospital, Boston, 02114, USA.
Liu
Y
Y
Ruvkun
G
G
D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D005809:Genes, Regulator; D018398:Homeodomain Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009420:Nervous System / Q000196:embryology*; D050809:POU Domain Factors; D014157:Transcription Factors / Q000235:genetics*
D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D050809:POU Domain Factors; D014157:Transcription Factors; C081539:unc-86 protein, C elegans