A FISSION YEAST GENE ENCODING A PROTEIN THAT PREFERENTIALLY ASSOCIATES WITH CURVED DNA

We searched for fission yeast (Schizosaccharomyces pombe) proteins tha t preferentially bind to a synthetic curved DNA sequence, by means of a DNA-binding gel shift assay in the presence of an excess amount of a non-curved DNA sequence as a competitor. We identified such a protein in S. pombe. The protein, thus purified, has an apparent molecular we ight of 42 000, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was suggested that this protein (42 K-protein) recognizes and binds to a curved DNA structure in a given nucleotide sequence, although it also binds to a non-curved DNA sequence with low er affinity. As its putative coding sequence, a 1.9-kilobase genomic D NA from S. pombe was cloned and sequenced. Sequencing of a cDNA clone also revealed the existence of an open reading frame, with no intron, encoding a 381-amino-acid protein with a calculated molecular mass, 41 597. This protein appears to be located in the nucleus. The predicted protein sequence revealed that the 42 K-protein exhibits no significa nt similarity to any other known proteins, except to a hypothetical pr otein of Caenorhabditis elegans.