pos-1 encodes a cytoplasmic zinc-finger protein essential for germline specification in C. elegans.
Germ cells arise during early C. elegans embryogenesis from an invariant sequence of asymmetric divisions that separate germ cell precursors from somatic precursors. We show that maternal-effect lethal mutations in the gene pos-1 cause germ cell precursors to inappropriately adopt somatic cell fates. During early embryogenesis, pos-1 mRNA and POS-1 protein are present predominantly in the germ precursors. POS-1 is a novel protein with two copies of a CCCH finger motif previously described in the germline proteins PIE-1 and MEX-1 in C. elegans, and in the mammalian TIS11/Nup475/TTP protein. However, mutations in pos-1 cause several defects in the development of the germline blastomeres that are distinct from those caused by mutations in pie-1 or mex-1. The earliest defect detected in pos-1 mutants is the failure to express APX-1 protein from maternally provided apx-1 mRNA, suggesting that POS-1 may have an important role in regulating the expression of maternal mRNAs in germline blastomeres.
Tabara
H
H
Department of Genetics, Graduate University of Advanced Studies and Gene Network Lab, National Institute of Genetics, Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Mishima 411, Japan.
Hill
R J
RJ
Mello
C C
CC
Priess
J R
JR
Kohara
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001757:Blastomeres; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D029742:Caenorhabditis elegans Proteins; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D015222:Sodium Channels / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells; D014158:Transcription, Genetic; D016335:Zinc Fingers / Q000235:genetics*
D029742:Caenorhabditis elegans Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D015222:Sodium Channels; C489774:apx-1 protein, C elegans; C104694:mex-1 protein, C elegans; C100950:pie-1 protein, C elegans