The lin-4 regulatory RNA controls developmental timing in Caenorhabditis elegans by blocking LIN-14 protein synthesis after the initiation of translation.
lin-4 encodes a small RNA that is complementary to sequences in the 3' untranslated region (UTR) of lin-14 mRNA and that acts to developmentally repress the accumulation of LIN-14 protein. This repression is essential for the proper timing of numerous events of Caenorhabditis elegans larval development. We have investigated the mechanism of lin-4 RNA action by examining the fate of lin-14 mRNA in vivo during the time that lin-4 RNA is expressed. Our results indicate that the rate of synthesis of lin-14 mRNA, its state of polyadenylation, its abundance in the cytoplasmic fraction, and its polysomal sedimentation profile do not change in response to the accumulation of lin-4 RNA. Our results indicate that association of lin-4 RNA with the 3' UTR of lin-14 mRNA permits normal biogenesis of lin-14 mRNA, and normal translational initiation, but inhibits step(s) thereafter, such as translational elongation and/or the release of stable LIN-14 protein.
Olsen
P H
PH
Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA.
Ambros
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D020413:3' Untranslated Regions / Q000235:genetics; D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology*; D029742:Caenorhabditis elegans Proteins; D002499:Centrifugation, Density Gradient; D015536:Down-Regulation / Q000235:genetics; D015801:Helminth Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D009687:Nuclear Proteins; D009693:Nucleic Acid Hybridization; D011061:Poly A / Q000235:genetics; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
D020413:3' Untranslated Regions; D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; C102669:LIN-14 protein, C elegans; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA