A conditional yeast mutant deficient in mRNA transport from nucleus to cytoplasm.
Transport of mRNA from nucleus to cytoplasm is critical for eukaryotic gene expression; however, the mechanism of export is unknown. Selection and screening procedures have therefore been used to obtain a family of temperature-sensitive conditional mutants of Saccharomyces cerevisiae that accumulate poly(A)+ RNA in the nucleus when incubated at 37 degrees C, as judged by in situ hybridization. In one such mRNA transport mutant, mtr1-1, RNA synthesis continues, the export of poly(A)+ RNA is inhibited, intranuclear poly(A)+ is remarkably stable, and protein synthesis gradually stops. Thus, there is no tight coupling between RNA synthesis and export. The export lesion is reversible. Although mRNA export is clearly not a default option, neither inhibition of protein synthesis, inhibition of mRNA splicing, nor inhibition of poly(A)-binding protein function blocks export of the average poly(A)+, as judged by in situ hybridization. Further analysis of the family of mtr mutants should help map the path of RNA transport.
Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106.
T
T
Kadowaki
Y
Y
Zhao
A M
AM
Tartakoff
D000255:Adenosine Triphosphate / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D005656:Fungal Proteins / Q000096:biosynthesis; D005800:Genes, Fungal; D007700:Kinetics; D009154:Mutation; D010641:Phenotype; D011061:Poly A / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D013696:Temperature; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D005656:Fungal Proteins; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D000255:Adenosine Triphosphate; D001616:beta-Galactosidase