Sugino Hidehiko, Yanase Hiroshi, Hamada Shun, Kurokawa Ken, Asakawa Shuichi, Shimizu Nobuyoshi, Yagi Takeshi
Genome Information Research Center, Osaka University, 3-1, Yamadaoka Suita, Osaka 565-0871, Japan.
Biochem Biophys Res Commun. 2004 Apr 2;316(2):437-45. doi: 10.1016/j.bbrc.2004.02.067.
CNR/Pcdhalpha family proteins have been first identified as a receptor family that corporate with Fyn, a family of the Src family of tyrosine kinase, and known as synaptic cadherins. Here we report the complete genomic sequence and organization of the chicken (Gallus gallus) CNR/Pcdhalpha The total length of chicken CNR/Pcdhalpha is 177kb. The chicken CNR/Pcdhalpha cluster encodes 12 variable and 3 constant exons. The genomic organizations of the chicken, rat, mouse, and human CNR/Pcdhalpha are basically orthologous. The constant-region exons (CP1, CP2, and CP3) are highly conserved between chicken and mammals, with percent identities of 90.9%, 90.7%, and 91.8% at the amino-acid level for chicken versus rat, mouse, and human, respectively. In contrast, the percent identities of the variable-region exons between chicken and mammals were lower: 51.8%, 51.3%, and 52.7%, on average, for chicken versus rat, mouse, and human, respectively, at the amino-acid level. Moreover, the chicken variable-region exons (from v1 to v12) are highly conserved paralogously (91.4%: nucleic acid, 92.4%: amino acid) in comparison with those of mammals. The CG content of each variable exon in the chicken (v1 to v12) is 74% on average and the CpG dinucleotide frequency in each variable-region exon is twice that of mammals. Due to the high CG content, chicken variable exons (from v1 to v12) encode 3 to 4 frame-shifted open reading frames, which span 1.5-3.0kb, in both the sense and anti-sense orientations.
CNR/Pcdhalpha家族蛋白最初被鉴定为一个与Fyn（酪氨酸激酶Src家族的一个成员）协同作用的受体家族，被称为突触钙黏蛋白。在此，我们报告鸡（原鸡）CNR/Pcdhalpha的完整基因组序列和结构。鸡CNR/Pcdhalpha的全长为177kb。鸡CNR/Pcdhalpha基因簇编码12个可变外显子和3个恒定外显子。鸡、大鼠、小鼠和人类CNR/Pcdhalpha的基因组结构基本是直系同源的。恒定区外显子（CP1、CP2和CP3）在鸡和哺乳动物之间高度保守，鸡与大鼠、小鼠和人类在氨基酸水平上的同一性百分比分别为90.9%、90.7%和91.8%。相比之下，鸡和哺乳动物之间可变区外显子的同一性百分比则较低：在氨基酸水平上，鸡与大鼠、小鼠和人类的平均同一性百分比分别为51.8%、51.3%和52.7%。此外，与哺乳动物相比，鸡的可变区外显子（从v1到v12）在旁系同源性上高度保守（核酸水平为91.4%，氨基酸水平为92.4%）。鸡（v1到v12）每个可变外显子的CG含量平均为74%，每个可变区外显子中CpG二核苷酸的频率是哺乳动物的两倍。由于CG含量高，鸡的可变外显子（从v1到v12）在正义和反义方向上都编码3到4个移码开放阅读框，跨度为1.5 - 3.0kb。
