Organization of the transcriptional unit of a human class II histocompatibility antigen: HLA-DR heavy chain.

A total of 5724 base pairs of a recombinant phage DNA containing a human HLA-DR heavy chain gene including flanking regions has been analyzed. The regions corresponding to all the exons have been identified. The sites of initiation of transcription and polyadenylation have been determined. A large intron of 2399 base pairs separates the first exon containing the 5' untranslated region and the signal peptide from the second exon containing the N-terminal peptide domain.