Sequence Analysis of a 685-kb Genomic Region on Chromosome 3p22-p21.3 That Is Homozygously Deleted in a Lung Carcinoma Cell Line

Frequent chromosomal aberrations and/or losses of heterozygosityinvolving the short arm of chromosome 3 in carcinomas of thelung, kidney and other tissues imply that multiple putativetumor suppressor genes may be present on this chromosomal arm.To search for one of these genes, we determined DNA sequencesin the genomic region at 3p22–21.3 where we had previouslydetected a homozygous deletion in a lung cancer cell line. TheDNA sequence results of an about 685-kb region indicated thatthe size of the homozygously deleted segment was 638,489 bp,in which we identified only four genes including the integrinRLC and the trans-Golgi p230 genes, both reported previously.The predicted amino acid sequences of one of the two novel genesshowed high homology to villin, a human cytoskeleton protein;those of the other gene, termed HYA22, revealed significanthomology to YA22, a hypothetical protein predicted from DNAsequences of Schizosaccharomyces pombe. The computer programsHEXON or GRAIL were able to predict three-fourths of the exons;the smallest exon predicted by either program was 46 base pairs.Repetitive sequences contained in the genomic region included151 copies of the Alu sequence (1 copy/every 4.5 kb), 19 copiesof the L1 sequence (1 copy/every 36 kb) , and 10 copies of theTHE sequence.