RESUMO
We have cloned a novel human cDNA, INPPL1 (GenBank Accession No. L36818), which maps to 11q23. The corresponding mRNA is 4657 nt in length and is widely expressed in both fetal and adult tissues. An open reading frame of 3441 nt encodes a putative polypeptide that shares several domains with inositol triphosphate phosphatases. Several polymorphisms have been mapped to the 3'-untranslated region, yet the putative coding region showed no polymorphisms in nine independent cDNA samples.
Assuntos
Cromossomos Humanos Par 11 , Hominidae/genética , Monoéster Fosfórico Hidrolases/genética , Adulto , Sequência de Aminoácidos , Animais , Mapeamento Cromossômico , Clonagem Molecular , Sequência Conservada , DNA Complementar , Feto , Humanos , Dados de Sequência Molecular , Fases de Leitura Aberta , Monoéster Fosfórico Hidrolases/biossíntese , Polimorfismo Genético , Homologia de Sequência de AminoácidosRESUMO
The delay of S-phase following treatment of yeast cells with DNA-damaging agents is an actively regulated response that requires functional RAD9 and RAD24 genes. An analysis of cell cycle arrest indicates the existence of (at least) two checkpoints for damaged DNA prior to S-phase; one at START (a G1 checkpoint characterized by pheromone sensitivity of arrested cells) and one between the CDC4- and CDC7-mediated steps (termed the G1/S checkpoint). When a dna1-1 mutant (that affects early events of replicon initiation) also carries a rad9 deletion mutation, it manifests a failure to arrest in G1/S following incubation at the restrictive temperature. This failure to execute regulated G1/S arrest is correlated with enhanced thermosensitivity of colony-forming ability. In an attempt to characterize the signal for RAD9 gene-dependent G1 and G1/S cell cycle arrest, we examined the influence of the continued presence of unexcised photoproducts. In mutants defective in nucleotide excision repair, cessation of S-phase was observed at much lower doses of UV radiation compared to excision-proficient cells. However, this response was not RAD9-dependent. We suggest that an intermediate of nucleotide excision repair, such as DNA strand breaks or single-stranded DNA tracts, is required to activate RAD9-dependent G1 and G1/S checkpoint controls.
Assuntos
Proteínas de Ciclo Celular , Ciclo Celular/efeitos da radiação , Dano ao DNA , Proteínas de Ligação a DNA , Endodesoxirribonucleases , Peptídeos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/efeitos da radiação , Ciclo Celular/genética , Citometria de Fluxo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fase G1/genética , Fase G1/efeitos da radiação , Deleção de Genes , Genes Fúngicos , Genótipo , Peptídeos e Proteínas de Sinalização Intracelular , Fator de Acasalamento , Biossíntese Peptídica , Feromônios/biossíntese , Mapeamento por Restrição , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/crescimento & desenvolvimento , Especificidade da Espécie , Transcrição GênicaRESUMO
A newly characterized rad1 missense mutation (rad1-20) in the yeast Saccharomyces cerevisiae maps to a region of the Rad1 polypeptide known to be required for Rad1-Rad10 complex formation. The UV sensitivity of the rad1-20 mutant can be partially and specifically corrected by overexpression of wild-type Rad10 protein. These results suggest that complex formation between the Rad1 and Rad10 proteins is required for nucleotide excision repair.
Assuntos
Dano ao DNA , Proteínas de Ligação a DNA , Endonucleases , Proteínas Fúngicas/metabolismo , Genes Fúngicos , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efeitos da radiação , Raios Ultravioleta , Sequência de Aminoácidos , Sequência de Bases , Enzimas Reparadoras do DNA , Relação Dose-Resposta à Radiação , Proteínas Fúngicas/genética , Fases de Leitura Aberta , Mutação Puntual , Mapeamento por Restrição , Saccharomyces cerevisiae/genética , Endonucleases Específicas para DNA e RNA de Cadeia SimplesRESUMO
Exposure of the yeast Saccharomyces cerevisiae to ultraviolet (UV) light, the UV-mimetic chemical 4-nitroquinoline-1-oxide (4NQO), or gamma radiation after release from G1 arrest induced by alpha factor results in delayed resumption of the cell cycle. As is the case with G2 arrest following ionizing radiation damage [Weinert, T. A. & Hartwell, L. H. (1988) Science 241, 317-322], the normal execution of DNA damage-induced G1 arrest depends on a functional yeast RAD9 gene. We suggest that the RAD9 gene product may interact with cellular components common to the G1/S and G2/M transition points in the cell cycle of this yeast. These observations define a checkpoint in the eukaryotic cell cycle that may facilitate the repair of lesions that are otherwise processed to lethal and/or mutagenic damage during DNA replication. This checkpoint apparently operates after the mating pheromone-induced G1 arrest point but prior to replicative DNA synthesis, S phase-associated maximal induction of histone H2A mRNA, and bud emergence.
