PIE-1 is a bifunctional protein that regulates maternal and zygotic gene expression in the embryonic germ line of Caenorhabditis elegans.
The CCCH zinc finger protein PIE-1 is an essential regulator of germ cell fate that segregates with the germ lineage during the first cleavages of the Caenorhabditis elegans embryo. We have shown previously that one function of PIE-1 is to inhibit mRNA transcription. Here we show that PIE-1 has a second function in germ cells; it is required for efficient expression of the maternally encoded Nanos homolog NOS-2. This second function is genetically separable from PIE-1's inhibitory effect on transcription. A mutation in PIE-1's second CCCH finger reduces NOS-2 expression without affecting transcriptional repression and causes primordial germ cells to stray away from the somatic gonad, occasionally exiting the embryo entirely. Our results indicate that PIE-1 promotes germ cell fate by two independent mechanisms as follows: (1) inhibition of transcription, which blocks zygotic programs that drive somatic development, and (2) activation of protein expression from nos-2 and possibly other maternal RNAs, which promotes primordial germ cell development.
Tenenhaus
C
C
Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
Subramaniam
K
K
Dunn
M A
MA
Seydoux
G
G
D000818:Animals; D030801:Animals, Genetically Modified; D015153:Blotting, Western; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D019070:Cell Lineage; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015801:Helminth Proteins / Q000378:metabolism; D017403:In Situ Hybridization; D008297:Male; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009035:Mothers; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism* / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013997:Time Factors; D014158:Transcription, Genetic; D019076:Transgenes
C577515:Ama1 protein, S cerevisiae; D029742:Caenorhabditis elegans Proteins; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D015801:Helminth Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; C400703:nos-2 protein, C elegans; C100950:pie-1 protein, C elegans