Identification and isolation of the gene encoding the small subunit of XXXX reductase from @entity375 : DNA damage-inducible gene required for mitotic viability.

@entity1522 @entity1978 @entity535 @entity19685 @entity9868 @entity377 @entity19687 @entity19686 @entity375 @entity2151
@entity2151 reductase catalyzes the first step in the pathway for the production of deoxyribonucleotides needed for DNA synthesis. The gene encoding the small subunit of @entity2151 reductase was isolated from a @entity375 genomic DNA expression library in lambda gt11 by a fortuitous cross-reaction with anti-RecA antibodies. The cross-reaction was due to an identity between the last four @entity1522 of each protein. The gene has been named @entity19685 and is centromere linked on chromosome X. The @entity377 sequence was determined, and the deduced @entity535 sequence, 399 @entity1522 , shows extensive homology with other eucaryotic @entity2151 reductases. Transplason mutagenesis was used to disrupt the @entity19685 gene. A novel assay using colony color sectoring was developed to demonstrate visually that @entity19685 is essential for mitotic viability. @entity19685 encodes a 1.5-kilobase mRNA whose levels increase 18-fold after treatment with the DNA-damaging agent @entity1978 . @entity19687 was also found to be inducible by DNA damage, but @entity19686 and @entity9868 were not inducible by @entity1978 . The expression of these genes defines a new mode of regulation for enzymes involved in DNA biosynthesis and sharpens our picture of the events leading to DNA repair in eucaryotic cells.
