The PIE-1 protein and germline specification in C. elegans embryos.
Totipotent germline blastomeres in Caenorhabditis elegans contain, but do not respond to, factors that promote somatic differentiation in other embryonic cells. Mutations in the maternal gene pie-1 result in the germline blastomeres adopting somatic cell fates. Here we show that pie-1 encodes a nuclear protein, PIE-1, that is localized to the germline blastomeres throughout early development. During division of each germline blastomere, PIE-1 initially associates with both centrosomes of the mitotic spindle. However, PIE-1 rapidly disappears from the centrosome destined for the somatic daughter, and persists in the centrosome of the daughter that becomes the next germline blastomere. The PIE-1 protein contains potential zinc-finger motifs also found in the mammalian growth-factor response protein TIS-11/NUP475 (refs 4-7). The localization and genetic properties of pie-1 provide an example of a repressor-based mechanism for preserving pluripotency within a stem cell lineage.
Mello
C C
CC
Department of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104, USA.
Schubert
C
C
Draper
B
B
Zhang
W
W
Lobel
R
R
Priess
J R
JR
D000595:Amino Acid Sequence; D000818:Animals; D001757:Blastomeres / Q000166:cytology; D017173:Caenorhabditis elegans / Q000166:cytology / Q000196:embryology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D019070:Cell Lineage / Q000235:genetics; D018385:Centrosome / Q000502:physiology; D003001:Cloning, Molecular; D017238:Genes, Helminth; D005854:Germ Cells / Q000166:cytology*; D015801:Helminth Proteins / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid; D016335:Zinc Fingers / Q000235:genetics
D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; C100950:pie-1 protein, C elegans