ISOLATION AND CHARACTERIZATION OF NOVEL BRAIN EXPRESSED SEQUENCES FROM A CHROMOSOME 21 LIBRARY

Abstract

A flow-sorted chromosome 21 library was used to isolate novel brain expressed sequences. The library was screened with 32P labelled cDNA derived from human adult brain polyadenylated RNA. Clones corresponding to transcribed brain sequences were isolated and purified. Forty-six clones were initially isolated. Five were studied further. Two contained unique sequences and were used to screen for cDNAs from various libraries. Among the positive cDNAs isolated were several sequences belonging to the human Alu and Kpn middle repetitive DNA families. Two cDNAs whose relevant mRNAs showed tissue-specific expression were also isolated. One probably represented the bovine equivalent of the rat MRC OX-2 cDNA. The other clone, ds9F, was a hitherto uncharacterized cDNA whose corresponding mRNA(s) showed brain specific expression and developmental regulation. Its ubiquitous presence In all brain regions and vertebrate species examined indicated a very basic and central role in brain development and function.