COMPLEX PATTERNS OF SEQUENCE VARIATION AND MULTIPLE 5' AND 3' ENDS ARE FOUND AMONG TRANSCRIPTS OF THE ERYTHROID ANKYRIN GENE

The structural protein ankyrin functions in red blood cells to link th e spectrin-based membrane skeleton to the plasma membrane. Ankyrin pro teins are now known to occur in most cell types, and two distinct anky rin genes have been identified (erythroid (Ank-1) and brain (Ank-2)). We have characterized transcripts of the mouse erythroid ankyrin gene by cDNA cloning and DNA sequencing. Ank-1 transcripts of 7.5 and 9.0 k ilobases are found in erythroid tissues, and a 9.0-kilobase transcript is found in cerebellum. RNA hybridization blot analysis of 13 additio nal mouse tissues has detected four novel Ank-1 transcripts (5.0, 3.5, 2.0, and 1.6 kilobases in size). Sequencing of Ank-1 cDNA clones isol ated from mouse reticulocyte, spleen, and cerebellar libraries has ide ntified (i) multiple 5' ends that indicate possible multiple promoters ; (ii) alternative polyadenylation sites that probably account for the 7.5- and 9.0-kilobase size difference; (iii) a variety of small inser tions and deletions that could produce transcripts (and ultimately pro teins) of nearly identical size, but different functions; and (iv) clo nes with large deletions of coding sequence that account for the small er transcripts seen in spleen, skeletal muscle, and heart.