Organization and expression of the chicken N-myc gene.
We cloned the chicken N-myc gene and analyzed its structure and expression. We found that it consisted of three exons with coding regions in exons 2 and 3. Comparison to mammalian N-myc genomic sequence indicated that nucleotide sequences of the 5'-flanking region, noncoding exon 1, and introns were not conserved, but coding and 3' noncoding sequences showed significant homology to mammalian N-myc. Alignment of deduced amino acid sequences of chicken and mammalian N-myc proteins revealed nine conserved domains interrupted by different lengths of nonhomologous sequences. Two of the domains were specific to N-myc proteins, and the other seven were common to c-myc proteins. Northern blot (immunoblot) and in situ hybridization analyses of 3.5-day-old chicken embryos revealed that high-level expression of the N-myc gene was confirmed to certain tissues, e.g., the central nervous system, neural crest derivatives, and mesenchyme of limb buds. In the beak and limb primordia, N-myc expression in the mesenchyme was higher toward the distal end, suggesting possible involvement in positional assignment of the tissue within the rudimentary structures.
Sawai
S
S
Department of Molecular Biology, School of Science, Nagoya University, Japan.
Kato
K
K
Wakamatsu
Y
Y
Kondoh
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002642:Chick Embryo; D002645:Chickens / Q000235:genetics*; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005091:Exons; D005455:Fluorescent Antibody Technique; D005796:Genes; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping
D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D004247:DNA