title: Characterization of the ptr6(+) gene in fission yeast: a possible involvement of a transcriptional coactivator TAF in nucleocytoplasmic transport of mRNA.
abstract: Transport of mRNA from the nucleus to the cytoplasm is one of the important steps in gene expression in eukaryotic cells. To elucidate a mechanism of mRNA export, we identified a novel ptr [poly(A)+ RNA transport] mutation, ptr6, which causes accumulation of mRNA in the nucleus and inhibition of growth at the nonpermissive temperature. The ptr6(+) gene was found to encode an essential protein of 393 amino acids, which shares significant homology in amino acid sequence with yTAFII67 of budding yeast Saccharomyces cerevisiae and human hTAFII55, a subunit of the general transcription factor complex TFIID. A Ptr6p-GFP fusion protein is localized in the nucleus, suggesting that Ptr6p functions there. Northern blot analysis using probes for 10 distinct mRNAs showed that the amount of tbp+ mRNA encoding the TATA-binding protein is increased five- to sixfold, whereas amounts of others are rapidly decreased at the nonpermissive temperature in ptr6-1. ptr6 has no defects in nuclear import of an NLS-GFP fusion protein. These results suggest that Ptr6p required for mRNA transport is a Schizosaccharomyces pombe homologue of yTAFII67 and hTAFII55. This is the first report suggesting that a TAF is involved in the nucleocytoplasmic transport of mRNA in addition to the transcription of the protein-coding genes.
authors.affiliation: Department of Biology, Faculty of Science, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shibuya
authors.forename: S
authors.initials: S
authors.lastname: Tsuneyoshi
authors.forename: A K
authors.initials: AK
authors.lastname: Azad
authors.forename: S
authors.initials: S
authors.lastname: Urushiyama
authors.forename: Y
authors.initials: Y
authors.lastname: Ohshima
authors.forename: T
authors.initials: T
authors.lastname: Tani
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D005434:Flow Cytometry; D015870:Gene Expression; D005809:Genes, Regulator; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012568:Schizosaccharomyces / Q000235:genetics*; D029702:Schizosaccharomyces pombe Proteins; D035381:TATA-Binding Protein Associated Factors; D013696:Temperature; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D014158:Transcription, Genetic
chemical_list: D009687:Nuclear Proteins; C121264:Ptr6 protein, S pombe; D012333:RNA, Messenger; D029702:Schizosaccharomyces pombe Proteins; C091537:TAF7 protein, human; D035381:TATA-Binding Protein Associated Factors; D015534:Trans-Activators; D035362:Transcription Factor TFIID; D014157:Transcription Factors