Gerber-Huber S, Nardelli D, Haefliger J A, Cooper D N, Givel F, Germond J E, Engel J, Green N M, Wahli W
Nucleic Acids Res. 1987 Jun 25;15(12):4737-60. doi: 10.1093/nar/15.12.4737.
In Xenopus laevis four estrogen-responsive genes are expressed simultaneously to produce vitellogenin, the precursor of the yolk proteins. One of these four genes, the gene A2, was sequenced completely, as well as cDNAs representing 75% of the coding region of the gene. From this data the exon-intron structure of the gene was established, revealing 35 exons that give a transcript of 5,619 bp without the poly A-tail. This A2 transcript encodes a vitellogenin of 1,807 amino acids, whose structure is discussed with respect to its function. At the nucleic acid as well as at the protein level no extensive homologies with any sequences other than vitellogenin were observed. Comparison of the amino acid sequence of the vitellogenin A2 molecule with biochemical data obtained from the different yolk proteins allowed us to localize the cleavage products on the vitellogenin precursor as follows: NH2 - lipovitellin I - phosvitin (or phosvette II - phosvette I) - lipovitellin II - COOH.
在非洲爪蟾中，四个雌激素反应基因同时表达以产生卵黄蛋白原，即卵黄蛋白的前体。这四个基因中的一个，即A2基因，已被完全测序，同时还测定了代表该基因75%编码区的cDNA序列。根据这些数据确定了该基因的外显子-内含子结构，发现有35个外显子，其转录本长度为5619 bp（不包括聚腺苷酸尾）。该A2转录本编码一种含有1807个氨基酸的卵黄蛋白原，并结合其功能对其结构进行了讨论。在核酸和蛋白质水平上，除了卵黄蛋白原外，未观察到与任何其他序列有广泛的同源性。通过将卵黄蛋白原A2分子的氨基酸序列与从不同卵黄蛋白获得的生化数据进行比较，我们确定了卵黄蛋白原前体上的裂解产物如下：氨基端-脂卵黄蛋白I-磷卵黄蛋白（或磷卵黄蛋白II-磷卵黄蛋白I）-脂卵黄蛋白II-羧基端。
