Sarwal M M, Sontag J M, Hoang L, Brenner S, Wilkie T M
Genome Res. 1996 Dec;6(12):1207-15. doi: 10.1101/gr.6.12.1207.
We compare the complexity and organization of the G protein alpha subunit multigene family in the vertebrate genomes of mammals and the Japanese puffer fish Fugu rubripes. Fourteen Fugu G alpha genes were identified of the 16 genes characterized previously in mammals, including Fugu genes from the four classes of alpha subunits Gs, Gi, Gq, and G12. Fugu and mammalian G alpha coding sequences are highly homologous, and the intron/exon structure of the fish and mammalian orthologs is identical throughout the coding regions. A novel G alpha gene, G alpha p1, was also identified in Fugu rubripes and two other species of puffer fish. The complete sequence of Gnaz and the tandemly duplicated genes Gnai2 and Gnat1 were obtained from a Fugu genomic cosmid library. Introns in the puffer fish G alpha genes lacked repeat DNA sequences, other than simple sequence length repeats, and most introns were significantly shorter in Fugu than in mammalian orthologs. The compact genome of puffer fish provides a unique vertebrate model for characterizing multigene families and identifying novel genes directly from genomic DNA by PCR amplification with degenerate primers. The fact that Fugu encodes most, if not all, of the G protein alpha subunits identified in mammals strongly supports Fugu as a model organism for vertebrate genome research.
我们比较了哺乳动物和日本河豚红鳍东方鲀的脊椎动物基因组中G蛋白α亚基多基因家族的复杂性和组织情况。在先前已在哺乳动物中鉴定出的16个基因中，我们鉴定出了14个河豚Gα基因，包括来自Gs、Gi、Gq和G12这四类α亚基的河豚基因。河豚和哺乳动物的Gα编码序列高度同源，并且鱼类和哺乳动物直系同源基因的内含子/外显子结构在整个编码区域都是相同的。在红鳍东方鲀和另外两种河豚中还鉴定出了一个新的Gα基因Gαp1。从河豚基因组黏粒文库中获得了Gnaz以及串联重复基因Gnai2和Gnat1的完整序列。河豚Gα基因中的内含子除了简单序列长度重复外，缺乏重复DNA序列，并且河豚中的大多数内含子明显比哺乳动物直系同源基因中的内含子短。河豚紧凑的基因组为表征多基因家族以及通过用简并引物进行PCR扩增直接从基因组DNA中鉴定新基因提供了一个独特的脊椎动物模型。河豚编码了在哺乳动物中鉴定出的大多数（如果不是全部）G蛋白α亚基这一事实，有力地支持了河豚作为脊椎动物基因组研究的模式生物。
