Participation of XPB/Ptr8p, a component of TFIIH, in nucleocytoplasmic transport of mRNA in fission yeast.
To identify novel factors involved in nuclear mRNA export in Schizosaccharomyces pombe, we isolated and characterized the ptr8(+) gene, mutation of which causes nuclear accumulation of poly (A)(+) RNA. The ptr8(+) gene encodes an S. pombe homologue of human XPB, a component of TFIIH involved in nucleotide excision repair (NER) and transcription. A temperature-sensitive mutant of ptr8(+) (ptr8-1) was highly sensitive to UV irradiation, as are human XPB cells. Northern blot analysis demonstrated that the amount of total poly (A)(+) mRNAs does not decrease significantly at the nonpermissive temperature in ptr8-1 cells, whereas a pulse-labeling assay using (35)S-methionine showed that protein synthesis decreases rapidly after incubation of cells at the nonpermissive temperature, suggesting that ptr8-1 cells have a defect in nuclear mRNA export. In Saccharomyces cerevisiae, a mutation in the SSL2 gene encoding a homologue of Ptr8p also causes a block of mRNA export at the nonpermissive temperature. In addition, expression of human XPB in ptr8-1 cells rescued the ts phenotype and the mRNA export defects, suggesting that human XPB may also play a role in mRNA export. Furthermore, we revealed a functional interaction between Ptr8p and Tho2p, a component of the TREX complex involved in mRNA export. These results suggest that XPB/Ptr8p plays roles not only in NER and transcription, but also plays a conserved role in mRNA export.
Mizuki
Fumitaka
F
Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan.
Namiki
Takeshi
T
Sato
Hiroshi
H
Furukawa
Hiromi
H
Matsusaka
Tadao
T
Ohshima
Yasumi
Y
Ishibashi
Ryoko
R
Andoh
Tomoko
T
Tani
Tokio
T
D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D002466:Cell Nucleolus / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D003057:Cockayne Syndrome / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D011061:Poly A / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D016415:Sequence Alignment; D013696:Temperature; D051758:Transcription Factor TFIIH / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
C518585:Ptr8 protein, S pombe; D012333:RNA, Messenger; C489575:SSL2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; D051758:Transcription Factor TFIIH; D011061:Poly A; D004265:DNA Helicases