Journal of Microbiology

The Schizosaccharomyces pombe Proteins that Bind to the Human HnRNPA1 Winner RNA: Kim , Jeong Kook; J. Microbiol. 1997;35(4):327-333.

Abstract: Although extensively characterized in human cells, no heterogeneous nuclear ribonucleoprotein(hnRNP) has been found in the fission yeast Schizosaccharomyces pombe which is amenable to genetic studies and more similar to mammals than Saccharomyces cerevisiae is in terms of RNA processing. As a first step to characterize hnRNPs from S. pombe, attempt was made to find human hnRNP A1 homologs from S. pombe. The RNA molecule (A1 winner) containing the consensus high-affinity hnRNP A1 binding site (UAGGGA/U) was synthesized in vitro and used in an ultraviolet(UV) light-induced protein-RNA cross-linking assay. A number of S, pombe proteins bound to the A1 winner RNA. An approximately 50-kDa protein(p50) cross-linked more efficiently to the A1 winner RNA than other proteins. The p50 protein did not cross-link to a nonspecific RNA, but rather to the A1-5’ SS RNA in which the consensus 5’ splice junction sites of S. pombe introns were abolished. This suggests that the p50 protein, however, did not bind to the single-stranded DNA to shich the human hnRNP A1 could bind and be eluted with 0.5M NaCl. Further analysis should reveal more features of this RNA-binding protein.

A Novel UV-Sensitivity Mutation Induces Nucleotide Excision Repair Phenotype and Shows Epistatic Relationships with UvsF and UvsB Groups in Aspergillus nidulans: F. Baptista , M. A. A. Castro-Prado; J. Microbiol. 2001;39(2):102-108.

Abstract: DNA damage response has a central role in the maintenance of genomic integrity while mutations in related genes may result in a range of disorders, including neoplasic formations. The uvsZ1 characterized in this report is a novel uvs mutation in Aspergillus nidulans, resulting in a nucleotide excision repair (NER) phenotype: UV-sensitivity before DNA synthesis (quiescent cells), high UV-induced mutation frequency and probable absence of involvement with mitotic and meiotic recombinations. The mutation is recessive and non-allelic to the previously characterized uvsA101 mutation, also located on the paba-y interval on chromosome I. uvsZ1 showed wild-type sensitivity to MMS, which suggests non-involvement of this mutation with BER. Epitasis tests showed that the uvsZ gene product is probably involved in the same repair pathways as UVSB or UVSH proteins. Although mutations in these proteins result in an NER phenotype, UVSB is related with cell cycle control and UVSH is associated with the post-replicational repair pathway. The epistatic interaction among uvsZ1 and uvsB413 and uvsH77 mutations indicates that different repair systems may be related with the common steps of DNA damage response in Aspergillus nidulans.

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