Abstract
The sequences of a 51-kb region containing the cluster of five rat γ-crystallin-coding genes (CRYG) and of a 7-kb region surrounding the sixth rat CRYG gene were determined. Approximately 78 % of the total sequence represents intergenic DNA. We also sequenced 22 kb of DNA from the human CRYG gene cluster. All CRYG genes are associated with CpG-rich regions. The sequence similarity between the human and rat gene regions drops sharply (to 65 % ) in intronic and 3 ' -flanking regions but decreases only gradually in the 5 ' -flanking region. Highly conserved regions (>80%) are found as far upstream as 1.5kb. Overall intergenic distances are conserved. The human region contains much more repetitive DNA (24% vs. 10%) but less simple-sequence (sps) DNA (0.7% vs. 4%) than the rat region. Almost all repeats and spsDNA elements are located in the intergenic region. The location of repetitive and spsDNA differs between the orthologous regions and these elements were probably inserted after the evolutionary separation of rat and man. The Alu repeats in man and the B3 repeats in the rat are close copies of their respective consensus sequences and bordered by virtually perfect repeats. In contrast, the B1 and B2 repeats in the rat have diverged considerably from the consensus sequence and the surrounding direct repeats are usually imperfect. Thus the dispersion of the B1 and B2 repeats in the rat probably preceded that of the B3 repeats. Within the rat genomic region the spacing of Z-DNA elements is surprisingly regular, they are located about 12kb apart. A search for putative matrix-associated regions suggests that the rat CRYG gene cluster is organized into two chromosomal domains.
Original language | English |
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Pages (from-to) | 201-213 |
Number of pages | 13 |
Journal | Gene |
Volume | 78 |
Issue number | 2 |
DOIs | |
Publication status | Published - 30 May 1989 |