title: Maf1 protein, repressor of RNA polymerase III, indirectly affects tRNA processing.
abstract: Maf1 is negative regulator of RNA polymerase III in yeast. We observed high levels of both primary transcript and end-matured, intron-containing pre-tRNAs in the maf1Δ strain. This pre-tRNA accumulation could be overcome by transcription inhibition, arguing against a direct role of Maf1 in tRNA maturation and suggesting saturation of processing machinery by the increased amounts of primary transcripts. Saturation of the tRNA exportin, Los1, is one reason why end-matured intron-containing pre-tRNAs accumulate in maf1Δ cells. However, it is likely possible that other components of the processing pathway are also limiting when tRNA transcription is increased. According to our model, Maf1-mediated transcription control and nuclear export by Los1 are two major stages of tRNA biosynthesis that are regulated by environmental conditions in a coordinated manner.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02 106 Warsaw, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Karkusiewicz
authors.forename: Tomasz W
authors.initials: TW
authors.lastname: Turowski
authors.forename: Damian
authors.initials: D
authors.lastname: Graczyk
authors.forename: Joanna
authors.initials: J
authors.lastname: Towpik
authors.forename: Nripesh
authors.initials: N
authors.lastname: Dhungel
authors.forename: Anita K
authors.initials: AK
authors.lastname: Hopper
authors.forename: Magdalena
authors.initials: M
authors.lastname: Boguta
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D008954:Models, Biological; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism; D012320:RNA Polymerase III / Q000235:genetics / Q000378:metabolism*; D012322:RNA Precursors / Q000096:biosynthesis* / Q000235:genetics; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D012331:RNA, Fungal / Q000096:biosynthesis* / Q000235:genetics; D012343:RNA, Transfer / Q000096:biosynthesis* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: C408090:Los1 protein, S cerevisiae; C104954:MAF1 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D012322:RNA Precursors; D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D012343:RNA, Transfer; D012320:RNA Polymerase III