Elgar G, Rattray F, Greystrong J, Brenner S
University of Cambridge, Department of Medicine, Addenbrookes Hospital, United Kingdom.
Genomics. 1995 Jun 10;27(3):442-6. doi: 10.1006/geno.1995.1075.
The p55 gene, which codes for a 55-kDa erythrocyte membrane protein, has been cloned and sequenced from the genome of the Japanese puffer fish Fugu rubripes (Fugu). This organism has the smallest recorded vertebrate genome and therefore provides an efficient way to sequence genes at the genomic level. The gene encoding p55 covers 5.5 kb from the beginning to the end of the coding sequence, four to six times smaller than the estimated size of the human gene, and is encoded by 12 exons. The structure of this gene has not been previously elucidated, but from this and other data we would predict a similar or identical structure in mammals. The predicted amino acid sequence of this gene in Fugu, coding for a polypeptide of 467 amino acids, is very similar to that of the human gene with the exception of the first two exons, which differ considerably. The predicted Fugu protein has a molecular weight (52.6 kDa compared with 52.3 kDa) and an isoelectric point very similar to those of human p55. In human, the p55 gene lies in the gene-dense Xq28 region, just 30 kb 3' to the Factor VIII gene, and is estimated to cover 20-30 kb. Its 5' end is associated with a CpG island, although there is no evidence that this is the case in Fugu. The small size of genes in Fugu and the high coding homology that they share with their mammalian equivalents, both in structure and sequence, make this compact vertebrate genome an ideal model for genomic studies.
编码一种55千道尔顿红细胞膜蛋白的p55基因，已从日本河豚红鳍东方鲀（Fugu）的基因组中克隆并测序。这种生物拥有已记录的最小脊椎动物基因组，因此提供了一种在基因组水平对基因进行测序的有效方法。编码p55的基因从编码序列的起始到结束覆盖5.5千碱基对，比人类基因的估计大小小四到六倍，由12个外显子编码。该基因的结构此前尚未阐明，但基于此及其他数据，我们预测其在哺乳动物中具有相似或相同的结构。河豚中该基因预测的氨基酸序列编码一个467个氨基酸的多肽，除了前两个外显子有很大差异外，与人基因的序列非常相似。预测的河豚蛋白的分子量（52.6千道尔顿，相比之下人类p55为52.3千道尔顿）和等电点与人类p55非常相似。在人类中，p55基因位于基因密集的Xq28区域，距离凝血因子VIII基因仅30千碱基对的3'端，估计覆盖20 - 30千碱基对。其5'端与一个CpG岛相关联，尽管没有证据表明河豚中也是如此。河豚基因的小尺寸以及它们与哺乳动物对应基因在结构和序列上共享的高编码同源性，使这个紧凑的脊椎动物基因组成为基因组研究的理想模型。
