Tada Motoki N, Senzaki Kouji, Tai Yuumi, Morishita Hirofumi, Tanaka Yusuke Z, Murata Yoji, Ishii Yasuyuki, Asakawa Shuichi, Shimizu Nobuyoshi, Sugino Hidehiko, Yagi Takeshi
KOKORO-Biology Group, Laboratories for Integrated Biology, Graduate School of Frontier Biosciences, Osaka University 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
Gene. 2004 Oct 13;340(2):197-211. doi: 10.1016/j.gene.2004.07.014.
We have examined the protocadherin (Pcdh) gene clusters of the zebrafish (Danio rerio). At least three sets of the Pcdh gene cluster were found in the zebrafish genome. Here, we describe the complete organization of the DrPcdh2 gene clusters. Classification by phylogenetic and transcript analyses revealed 7 DrPcdh2omicron, 20 DrPcdh2alphaa, 12 DrPcdh2alphab, and 1 DrPcdh2alphac variable exons upstream of the DrPcdh2alpha constant region exons in the DrPcdh2 gene cluster. The constant regions of the DrPcdh1alpha and DrPcdh2alpha genes in zebrafish were orthologs of those of the mammalian Pcdhalpha. These exons all encoded plural PXXP motifs in their cytoplasmic tails. The sequences of the variable exons were highly conserved within each family: DrPcdh2omicron, DrPcdh2alphaa, and DrPcdh2alphab. Transcript analysis revealed that zebrafish Pcdhs had alternatively spliced variants in the constant region that were not found in mammals. More gene clusters, more variable exons, and more alternative splicing variants were found in zebrafish than in mammals. Thus, although the Pcdhalpha families were common to diverse vertebrates, their gene number, structure, and transcripts were different between teleosts and mammals.
我们研究了斑马鱼（Danio rerio）的原钙黏蛋白（Pcdh）基因簇。在斑马鱼基因组中发现了至少三组Pcdh基因簇。在此，我们描述了DrPcdh2基因簇的完整结构。通过系统发育和转录分析分类显示，在DrPcdh2基因簇中，DrPcdh2α恒定区外显子上游有7个DrPcdh2οmicron、20个DrPcdh2αα、12个DrPcdh2αβ和1个DrPcdh2αc可变外显子。斑马鱼中DrPcdh1α和DrPcdh2α基因的恒定区是哺乳动物Pcdhα恒定区的直系同源物。这些外显子在其胞质尾部均编码多个PXXP基序。可变外显子的序列在每个家族（DrPcdh2οmicron、DrPcdh2αα和DrPcdh2αβ）内高度保守。转录分析显示，斑马鱼Pcdh在恒定区有选择性剪接变体，而在哺乳动物中未发现。与哺乳动物相比，斑马鱼中发现了更多的基因簇、更多的可变外显子和更多的选择性剪接变体。因此，尽管Pcdhα家族在不同脊椎动物中普遍存在，但硬骨鱼和哺乳动物之间它们的基因数量、结构和转录本有所不同。
