A conserved chromatin architecture marks and maintains the restricted germ cell lineage in worms and flies.
In C. elegans, mRNA production is initially repressed in the embryonic germline by a protein unique to C. elegans germ cells, PIE-1. PIE-1 is degraded upon the birth of the germ cell precursors, Z2 and Z3. We have identified a chromatin-based mechanism that succeeds PIE-1 repression in these cells. A subset of nucleosomal histone modifications, methylated lysine 4 on histone H3 (H3meK4) and acetylated lysine 8 on histone H4 (H4acetylK8), are globally lost and the DNA appears more condensed. This coincides with PIE-1 degradation and requires that germline identity is not disrupted. Drosophila pole cell chromatin also lacks H3meK4, indicating that a unique chromatin architecture is a conserved feature of embryonic germ cells. Regulation of the germline-specific chromatin architecture requires functional nanos activity in both organisms. These results indicate that genome-wide repression via a nanos-regulated, germ cell-specific chromatin organization is a conserved feature of germline maintenance during embryogenesis.
Biology Department, Emory University, Atlanta, GA 30322, USA.
Christine E
CE
Schaner
Girish
G
Deshpande
Paul D
PD
Schedl
William G
WG
Kelly
D000818:Animals; D001757:Blastomeres / Q000166:cytology / Q000502:physiology; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D019070:Cell Lineage; D002843:Chromatin / Q000378:metabolism*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology / Q000235:genetics*; D005854:Germ Cells / Q000502:physiology*; D006657:Histones / Q000378:metabolism; D008745:Methylation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009690:Nucleic Acid Conformation; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D002843:Chromatin; D029721:Drosophila Proteins; D006657:Histones; C459463:MEP-1 protein, C elegans; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D014157:Transcription Factors; C100950:pie-1 protein, C elegans; C070574:nos protein, Drosophila