A HIGHLY CONSERVED REGION UPSTREAM OF THE FIBRONECTIN ALTERNATIVE EXON EIIIA 3'-SPLICE-SITE INTERACTS WITH CELL-TYPE-SPECIFIC NUCLEAR PROTEINS

Sequencing of chicken fibronectin genomic DNA and interspecies sequenc e comparisons reveal a highly conserved region upstream of the alterna tively spliced exon EIIIA. UV-crosslinking of RNAs corresponding to th is region from the chicken and rat genes with HeLa nuclear extract dem onstrates that both RNAs interact with similar proteins. However, both RNAs crosslink to a 70 kDa protein present in nuclear extracts from c ells and tissues that include exon EIIIA, but not in extracts from tis sues that exclude the exon. This protein represents a candidate cell-t ype-specific factor involved in exon EIIIA inclusion. (C) 1998 Elsevie r Science B.V.