Isolation and characterization of 21 novel expressed DNA sequences from the distal region of human chromosome 4p.

We have established an approach to the isolation of expressed DNA sequences from a defined region of the human chromosome. The method relies on the direct screening of cDNA libraries using pooled single-copy microclones generated by a laser chromosome micro-dissection in conjunction with a single unique primer polymerase chain reaction (SUP-PCR) procedure. We applied this method to the distal region of human chromosome 4p (4p15-4pter), which contains the Huntington disease (HD) and the Wolf-Hirschhorn syndrome (WHS) loci. Twenty-one nonoverlapping and region-specific cDNA clones encoding novel genes were isolated in this manner. Ten of 21 clones were subregionally assigned to 4p16.1-4pter, and the remainder mapped to the region proximal to 4p16.1. Northern blot and reverse transcription followed by the PCR (RT-PCR) analysis revealed that 16 of these 21 clones detected transcripts in total RNA from human tissues. Our method is applicable to other chromosomal regions and is a powerful approach to the isolation of region-specific cDNA clones.