The essential protein Fap7 is involved in the oxidative stress response of Saccharomyces cerevisiae

Abstract

Pos9 (Skn7) is an important transcription factor that, together with Yap1, induces the expression of oxidative stress target genes in Saccharomyces cerevisiae. The activation of Pos9 upon an oxidative stress signal occurs post‐translationally. In a mutant screen for factors involved in the activation of a Pos9‐dependent reporter gene upon oxidative stress, we identified the mutant fap7‐1 (for factor activating Pos9). This point mutant failed to activate a Gal4‐Pos9 hybrid transcription factor, assayed by hydrogen peroxide‐induced GAL1‐lacZ reporter gene activities. Additionally, the fap7‐1 mutant strain was sensitive to oxidative stress and revealed slow growth on glucose compared with the wild type. The fap7‐1 mutation also affected the induction of the Pos9 target gene TPX1 and of a synthetic promoter previously identified to be regulated in a Yap1‐ and Pos9‐dependent manner. This lack of induction was specific as the fap7‐1 mutant response to other stresses such as sodium chloride or co‐application of both hydrogen peroxide and sodium chloride was not affected, as tested with the Pos9‐independent expression pattern of a TPS2‐lacZ reporter system. We identified the gene YDL166c to be allelic to the FAP7 gene and to be essential. Fluorescence microscopy of Fap7–GFP fusion proteins indicated a nuclear localization of the Fap7 protein. Our data suggest that Fap7 is a nuclear factor important for Pos9‐dependent target gene transcription upon oxidative stress.

ATP Binding to Hemoglobin Response Gene 1 Protein Is Necessary for Regulation of the Mating Type Locus in Candida albicans

“…Hbr1p P-loop Mutations Do Not Alter Growth Rate-The original S. cerevisiae mutant strain Fap7-1 was identified as an isolate that failed to activate a peroxide-sensitive promoter and possessed a slow growth phenotype (8). However, the growth rates of all the strains listed in Table 2 were similar, with doubling times of ϳ80 min at 30°C in YPD medium.…”

“…This is not consistent with Hbr1p being a functional ortholog of the AK family of nuclear enzymes (16 -19). The S. cerevisiae ortholog Fap7p has also been localized in the yeast nucleus (8), but its proposed function in the final step of 18 S rRNA maturation is cytoplasmic (11).…”

“…The yeast ortholog Fap7 is also an essential gene (8) and was initially shown to interact with Krr1p, the product of a gene required for ribosomal RNA processing (9). FAP7 heterozygosis also leads to an 18S rRNA processing defect (10) that can be recapitulated with the K20R mutation of its predicted phosphate-binding loop (P-loop) 3 (11).…”

“…FAP7 heterozygosis also leads to an 18S rRNA processing defect (10) that can be recapitulated with the K20R mutation of its predicted phosphate-binding loop (P-loop) 3 (11). In addition, a G19S mutation prevented oxidative stress-induced activation of a Gal4-Pos9 hybrid transcription factor, indicating an important functional role for this motif (8).…”

hCINAP is an atypical mammalian nuclear adenylate kinase with an ATPase motif: Structural and functional studies

“…11 In C. elegans, knockdown of the cAK6 gene results in growth suspension. 12 In yeast, Fap7p 13 interacts with ribosomal protein RPS14 and appears to be involved in pre-rRNA processing: a Walker B-motif mutant (D82AH84A) is unable to cleave the 20S pre-rRNA from 40S pre-rRNA particles. 14 In human cells, hCINAP was shown to interact directly with the carboxy-terminal tail of coilin, a marker protein of Cajal bodies (CBs), which are nuclear organelles involved in the maturation of UsnRNPs and snoRNPs en route to their sites of function in the nucleoplasm and nucleolus.…”