A cloned 13.3-kilobase (kb) region of rabbit genomic DNA contains a cluster of α-like globin genes arranged 5'-ψζ-(3.6 kb)-α1-(2.2 kb)-ψα-3'. Genomic blot hybridization data show that this is the major α-like globin gene cluster in rabbits, although a second α-globin gene (α2) is also detected. Repetitive sequences from the C family of short repeats flank the ψζ gene, and a new repetitive element, the F repeat is located 3' to ψα. The sequence was determined for a 4024-base pair (bp) segment that extends from 149 bp 5' to the cap site of α1 to 207 bp 3' to ψα. Gene α1 is functional and encodes one of the major allelic variants of rabbit α-globin. This gene has very short introns (77 bp in intron 1 and 83 bp in intron 2) and an unusual ATA box in the 5' flanking region (CTTAAA), which does function to promote transcription by RNA polymerase II in a cell-free system. Short (4 or 9 bp) G + C-rich repeats are interspersed throughout the flanking regions and the introns. Gene ψα cannot encode a globin polypeptide, and it is probably inactive. This is shown by the absence of a normal globin gene promoter, the replacement of the 5' untranslated sequence by tandem repeats of the sequence GCCCGCCGC, frameshift deletions in exon 2, and the modification of the polyadenylation signal to AGTAAA. The intergenic region between α1 and ψα is very G + C rich (65.7% G + C) and contains many short, tandem repeats. Gene ψζ hybridizes specifically to a human ζ-globin gene probe, but a partial sequence reveals frameshift mutations that probably make ψζ a pseudogene. Mammalian α-globin gene clusters vary in the presence or absence of pseudogenes, and if present, the position of the pseudogene differs in various gene clusters so far analyzed, the rabbit gene cluster is unique in the absence of duplicated α-globin genes that are undergoing concerted evolution.
|Original language||English (US)|
|Number of pages||10|
|Journal||Journal of Biological Chemistry|
|State||Published - Jan 1 1986|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology