Structure of the 5' flanking region of the gene encoding human glycophorin A and analysis of its multiple transcripts

Glycophorin A (GPA), the major sialoglycoprotein of human erythrocytes, is the carrier for blood group MN antigens and a receptor for viruses, bacteria and parasites. (1) Three distinct GPA mRNAs (1.0, 1.7 and 2.2 kb) have been previously identified in erythroid tissues by Northern-blot analysis. It is shown here by sequence analysis of several human fetal liver cDNAs, and by transcription start point (tsp) determination using primer extension analysis, that the production of the multiple GPA mRNAs is governed by poly(A) site choice generating 3'-untranslated regions of different length, and not by the tsp heterogeneity, since all messages exhibit the same cap site (tsp). (2) The structural gene encoding GPA has been recently cloned [Vignal et al., Eur. J. Biochem. 184 (1989) 337-344; Kudo and Fukuda, Proc. Natl. Acad. Sci. USA 86 (1989) 4619-4623] and we have now determined the sequence of a DNA genomic fragment upstream from the tsp. This fragment does not contain the typical TATA and CAAT boxes found in a number of tissue-specific genes, but contains typical motifs like the CACC, nuclear factor erythroid 1 and 2 elements, which have been identified recently in several erythroid-specific promoters, therefore suggesting that transcription of these genes might be regulated by the same or analogous factors.