ISOLATION OF 2 CONTIGS OF OVERLAPPING COSMIDS DERIVED FROM HUMAN CHROMOSOMAL BAND-3P21.1 AND IDENTIFICATION OF 5 NEW 3P21.1 GENES

Consistent loss Of DNA sequences from several regions on the short arm of human chromosome 3 has suggested that multiple tumor suppressor ge nes reside on chromosome 3p in various types of cancer cells. We have focused our efforts on an analysis of chromosomal band 3p21.1 since am inoacylase-1 (ACY1), which is localized to this band, has been shown t o have lower levels of expression in several small cell and non-small cell lung cancer cell lines. Starting with two cosmids within 3p21.1, D3S92 and D3S93, we have isolated two separate contigs of overlapping cosmids within 3p21.1, by screening a library of 5700 chromosome 3-spe cific cosmid clones. Detailed restriction maps for these two contigs s how that they contain multiple clusters of rare cutting restriction en donuclease sites. One contig extends for too kb and encompassed both A CY1 and D3S92, and the other extends about 80 kb around the D3S93 locu s. Many different restriction fragments derived from these two contigs were found to be evolutionarily conserved and hybridized to distinct message transcripts. These fragments were used to identify homologous cDNAs from an adenogastric cDNA library, and several of these cDNAs we re partially sequenced. We have identified Jive new genes from these t wo contigs and there is evidence to suggest that several additional ge nes reside within these cosmid contigs. The genes identified from 3p21 .1 were then hybridized to DNA, isolated from a series of lung cancel cell lines and matched normal and tumor DNA from lung cancer patients. No alterations were detected with any of these probes, both at the DN A or RNA levels. A similar analysis with DNA fragments derived from th ese two genomic regions also failed to detect any alterations.