Abstract
Asymmetric segregation of P granules during the first four divisions of the Caenorhabditis elegans embryo is a classic example of cytoplasmic partitioning of germline determinants. It is thought that asymmetric partitioning of P granule components during mitosis is essential to distinguish germline from soma. We have identified a mutant (pptr-1) in which P granules become unstable during mitosis and P granule proteins and RNAs are distributed equally to somatic and germline blastomeres. Despite symmetric partitioning of P granule components, pptr-1 mutants segregate a germline that uniquely expresses P granules during postembryonic development. pptr-1 mutants are fertile, except at high temperatures. Hence, asymmetric partitioning of maternal P granules is not essential to specify germ cell fate. Instead, it may serve to protect the nascent germline from stress.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Blastomeres / physiology*
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Caenorhabditis elegans / embryology*
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Caenorhabditis elegans / genetics
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Caenorhabditis elegans / metabolism
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Caenorhabditis elegans Proteins / genetics
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Caenorhabditis elegans Proteins / metabolism*
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Caenorhabditis elegans Proteins / physiology
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Cytoplasm / metabolism*
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Cytoplasmic Granules / physiology*
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Cytoplasmic Granules / ultrastructure
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Embryo, Nonmammalian / physiology
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Embryonic Development
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Germ Cells / physiology*
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Interphase
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Microscopy, Confocal
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Mitosis
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Mutation
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Nuclear Proteins / metabolism
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Protein Serine-Threonine Kinases / metabolism
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RNA, Helminth / metabolism*
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RNA-Binding Proteins / metabolism
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Recombinant Fusion Proteins / metabolism
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Zygote / physiology
Substances
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Caenorhabditis elegans Proteins
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Nuclear Proteins
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PGL-1 protein, C elegans
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RNA, Helminth
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RNA-Binding Proteins
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Recombinant Fusion Proteins
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pie-1 protein, C elegans
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pptr-1 protein, C elegans
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PAR-1 protein, C elegans
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Protein Serine-Threonine Kinases