emb-4 is a conserved gene required for efficient germline-specific chromatin remodeling during Caenorhabditis elegans embryogenesis.
In C. elegans, germline blastomeres are initially kept transcriptionally quiescent by the maternally loaded CCCH zinc-finger protein PIE-1. PIE-1 disappears upon the birth of the primordial germ cells Z2 and Z3, yet these cells appear to remain quiescent. We have previously demonstrated that there is a chromatin-based repression that succeeds PIE-1 degradation. The chromatin in Z2/Z3 loses certain histone modifications, including histone H3 lysine 4 dimethylation (H3K4me2), a conserved marker for transcriptionally competent chromatin. We find that mutations in the maternal-effect gene emb-4 cause defects in both PIE-1 degradation and germline-specific chromatin remodeling. emb-4 encodes a highly conserved protein with orthologs in fly, mouse, and human and has a subtle role in Notch signaling. The embryonic phenotype of emb-4 is consistent with a defect in the efficient and timely activation of developmental programs, including germline chromatin remodeling. We also find that, as in early somatic blastomeres, the degradation of PIE-1 in Z2/Z3 is facilitated by zinc-finger-interacting protein ZIF-1, and in the absence of either zif-1 or emb-4, PIE-1 is abnormally retained in Z2/Z3.
Checchi
Paula M
PM
Biology Department, Emory University, Atlanta, Georgia 30322, USA.
Kelly
William G
WG
D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D019070:Cell Lineage; D042002:Chromatin Assembly and Disassembly; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism*; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000502:physiology*; D006657:Histones / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D006657:Histones; D009687:Nuclear Proteins; C476529:ZIF-1 protein, C elegans; C100950:pie-1 protein, C elegans