Italian Mediterranean river buffalo CSN2 gene structure and promoter analysis.

The nucleotide sequence of the whole buffalo β-casein encoding gene (CSN2) plus 1,476 nt at the 5' flanking region and 51 nt at the 3' flanking region was determined. gene is spread over 10.2 kb and consists of 9 exons varying in length from 24 (exon 5) to 498 bp (exon 7) and 8 introns from 92 bp (intron 5) to 2259 bp (intron 1). Furthermore, highly conserved sequences, mainly located in the 5' flanking region, were found between this gene and the β-casein encoding genes of other species. comparison between the obtained promoter and exonic regions and buffalo sequences present in EMBL evidenced different polymorphic sites. Finally, 5 interspersed repeated elements (4 in the bovine CSN2 gene) were also identified at 3 different locations of the sequenced region: 5' untranscribed region, intron 1, and intron 4.