Nucleosomal repeat and the location of exons and introns in genes of collagens types I and VII

: Regions with a quasiperiodical location of exon--intron sites have been found in the loci of genes of I and VII type collagens (with a total length of exons more than 15% of the entire size of the locus). The periods observed are similar to periods typical for the nucleosomal level of the organization of chromatin. It was shown that the sites consisting of successively arranged exons and introns form groups involving two to five such regions of the same length. The groups encoding the fibrillar regions of the gene product contain more than 50% of exons. The regions are on the average 165 nt long, which is close to the minimal nucleosomal repeat length observed in some regions of the eukaryotic genome. In the nonfibrillar region of the gene of VII type collagen, groups of several exon-intron pairs with an average length of 227 nt were identified. The change in the length of exon-introns sites on going from the nonfibrillar to the fibrillar moiety occurs in a jump, which is clearly seen on a periodogram of the locus.