Conserved regulatory elements in the promoter region of the N-CAM gene.
Genomic clones containing 5'-flanking sequences, the first exon, and the entire first intron from the chicken N-CAM gene were characterized by restriction mapping and DNA sequencing. A > 600-bp segment that includes the first exon is very G + C-rich and contains a large proportion of CpG dinucleotides, suggesting that it represents a CpG island. SP-1 and AP-1 consensus elements are present, but no TATA- or CCAAT-like elements were found within 300 bp upstream of the first exon. Comparison of the chicken promoter region sequence with similar regions of the human, rat, and mouse N-CAM genes revealed that some potential regulatory elements including a "purine box" seen in mouse and rat N-CAM genes, one of two homeodomain binding regions seen in mammalian N-CAM genes, and several potential SP-1 sites are not conserved within this region. In contrast, high CpG content, a homeodomain binding sequence, an SP-1 element, an octomer element, and an AP-1 element are conserved in all four genes. The first intron of the chicken gene is 38 kb, substantially smaller than the corresponding intron from mammalian N-CAM genes. Together with previous studies, this work completes the cloning of the chicken N-CAM gene, which contains at least 26 exons distributed over 85 kb.
Colwell
G
G
Department of Anatomy and Cell Biology, University of Cincinnati Medical Center, Ohio 45267-0521.
Li
B
B
Forrest
D
D
Brackenbury
R
R
D000818:Animals; D001483:Base Sequence; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics*; D002645:Chickens; D003360:Cosmids; D008322:Mammals; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid
D015816:Cell Adhesion Molecules, Neuronal