Proteasomal regulation of the proliferation vs. meiotic entry decision in the Caenorhabditis elegans germ line.
Reproductive fitness in many animals relies upon a tight balance between the number of cells that proliferate in the germ line and the number of cells that enter meiosis and differentiate as gametes. In the Caenorhabditis elegans germ line, the GLP-1/Notch signaling pathway controls this balance between proliferation and meiotic entry. Here we describe the identification of the proteasome as an additional regulator of this balance. We show that a decrease in proteasome activity, through either genetic mutation or RNAi to core components of the proteasome, shifts this balance toward excess germ-line proliferation. We further demonstrate that there are likely two or more proteasome targets that contribute to excess germ-line proliferation when proteasome activity is reduced. One of these targets is likely a component or regulator of the Notch-signaling pathway, while the other functions on one of the two major redundant genetic pathways downstream of GLP-1/Notch signaling. We propose a model in which the proteasome degrades proteins that are necessary for proliferation as cells switch from proliferation to meiotic entry.
Macdonald
Lindsay D
LD
Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
Knox
Aaron
A
Hansen
Dave
D
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D005854:Germ Cells; D006066:Gonads / Q000254:growth & development*; D008540:Meiosis; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D011062:Polynucleotide Adenylyltransferase / Q000235:genetics / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction
D029742:Caenorhabditis elegans Proteins; C094448:GLD-1 protein, C elegans; C060620:Glp-1 protein, C elegans; D008562:Membrane Glycoproteins; D051880:Receptors, Notch; C491056:GLD-2 protein, C elegans; D011062:Polynucleotide Adenylyltransferase; D046988:Proteasome Endopeptidase Complex
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