ENHANCED ACCESS TO RARE BRAIN CDNAS BY PRESCREENING LIBRARIES - 207 NEW MOUSE-BRAIN ESTS

To use single-pass cDNA sequencing to characterize low-frequency cDNA clones from a region of the brain that includes the primary site of ne urodegeneration in human Parkinson disease, we have developed a prescr eening procedure using single brain region first-strand cDNA probes. S election of cDNA clones giving low hybridization signals allowed the e limination of clones resulting from abundant messages and enrichment f or clones corresponding to low-copy messages. Comparative sequencing o f standard and prescreened cDNA libraries (191 and 124 clones, respect ively) showed that this procedure raised the frequency of novel sequen ces encountered from 54 to 81%. The increased proportion of novel ESTs justifies the labor of prescreening. Automation of this procedure wil l accelerate the molecular description of genes expressed in any brain region, or any tissue, and represents a way to maximize access to cDN A sequences for human and mouse genome characterization. In total, the comparative sequencing experiments generated 207 new mouse and 11 new rat brain ESTs. (C) 1994 Academic Press, Inc.