title: PUF-8 suppresses the somatic transcription factor PAL-1 expression in C. elegans germline stem cells.
abstract: RNA-binding proteins of the PUF family are well conserved post-transcriptional regulators that control a variety of developmental processes. The C. elegans protein PUF-8 is essential for several aspects of germ cell development including the maintenance of germline stem cells (GSCs). To explore the molecular mechanisms underlying its function, we have identified 160 germline-expressed mRNAs as potential targets of PUF-8. We generated GFP::H2B-3' UTR fusions for 17 mRNAs to assay their post-transcriptional regulation in germ cells. Twelve transgenes were not expressed in the mitotic germ cells, and depletion of PUF-8 led to misexpression of six of them in these cells. In contrast, the expression of 3' UTR fusion of hip-1, which encodes the HSP-70 interacting protein, was dependent on PUF-8. These results indicate that PUF-8 may regulate the expression of its targets both negatively as well as positively. We investigated the PUF-8-mediated post-transcriptional control of one mRNA, namely pal-1, which encodes a homeodomain transcription factor responsible for muscle development. Our results show that PUF-8 binds in vitro to specific sequences within pal-1 3' UTR that are critical for post-transcriptional suppression in GSCs. Removal of PUF-8 resulted in PAL-1 misexpression, and PAL-1-dependent misexpression of the myogenic promoter HLH-1 in germ cells. We propose that PUF-8 protects GSCs from the influence of somatic differentiation factors such as PAL-1, which are produced in the maternal germline but meant for embryogenesis.
authors.affiliation: Department of Biological Sciences & Bioengineering, Indian Institute of Technology, Kanpur, India.
authors.forename: Rana
authors.initials: R
authors.lastname: Mainpal
authors.forename: Agarwal
authors.initials: A
authors.lastname: Priti
authors.forename: Kuppuswamy
authors.initials: K
authors.lastname: Subramaniam
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008938:Mitosis; D009124:Muscle Proteins; D018006:Myogenic Regulatory Factors / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins; D034622:RNA Interference; D012323:RNA Processing, Post-Transcriptional; D018510:RNA, Helminth / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors
chemical_list: D020413:3' Untranslated Regions; D029742:Caenorhabditis elegans Proteins; D018398:Homeodomain Proteins; C102175:MEX-3 protein, C elegans; D009124:Muscle Proteins; D018006:Myogenic Regulatory Factors; D009687:Nuclear Proteins; C510538:PUF-8 protein, C elegans; D018510:RNA, Helminth; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C066645:HLH-1 protein, C elegans; C068665:pal-1 protein, C elegans