PUF-8 suppresses the somatic transcription factor PAL-1 expression in C. elegans germline stem cells

Dev Biol. 2011 Dec 1;360(1):195-207. doi: 10.1016/j.ydbio.2011.09.021. Epub 2011 Sep 24.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions
  • Animals
  • Animals, Genetically Modified
  • Base Sequence
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Embryonic Stem Cells / cytology
  • Embryonic Stem Cells / metabolism*
  • Female
  • Gene Expression Regulation, Developmental
  • Genes, Helminth
  • Germ Cells / cytology
  • Germ Cells / metabolism*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Male
  • Mitosis
  • Muscle Proteins
  • Myogenic Regulatory Factors / genetics
  • Myogenic Regulatory Factors / metabolism
  • Nuclear Proteins
  • RNA Interference
  • RNA Processing, Post-Transcriptional
  • RNA, Helminth / genetics
  • RNA, Helminth / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcription Factors


  • 3' Untranslated Regions
  • Caenorhabditis elegans Proteins
  • Homeodomain Proteins
  • MEX-3 protein, C elegans
  • Muscle Proteins
  • Myogenic Regulatory Factors
  • Nuclear Proteins
  • PUF-8 protein, C elegans
  • RNA, Helminth
  • RNA, Messenger
  • RNA-Binding Proteins
  • Trans-Activators
  • Transcription Factors
  • HLH-1 protein, C elegans
  • pal-1 protein, C elegans