Westley B, Wyler T, Ryffel G, Weber R
Nucleic Acids Res. 1981 Aug 11;9(15):3557-74. doi: 10.1093/nar/9.15.3557.
cDNA clones containing sequences complementary to Xenopus laevis albumin mRNA have been identified in a collection of cDNA clones made from poly(A)+ RNA prepared from male Xenopus laevis liver. Although all the albumin cDNA clones crosshybridise, restriction enzyme and heteroduplex analysis show that there are 2 closely related albumin mRNA sequences. The 2 albumin mRNAs are only mismatched by 8% but could be isolated by positive selection using stringent hybridization conditions. Oocytes injected with the 2 purified mRNAs, secreted either the 68,000 or 74,000 dalton albumin into the culture medium showing that the 2 albumins of X. laevis serum are encoded in the 2 closely related mRNAs. Measurements of the abundance of albumin mRNA show that the 2 albumin mRNAs together account for about 9% of total poly(A)+ RNA in male Xenopus laevis liver but the mRNA coding for the 74,000 dalton mRNA is about twice as abundant as that coding for the 68,000 dalton mRNA.
在从雄性非洲爪蟾肝脏制备的聚腺苷酸加尾RNA（poly(A)+ RNA）构建的cDNA克隆文库中，已鉴定出含有与非洲爪蟾白蛋白mRNA序列互补的cDNA克隆。尽管所有白蛋白cDNA克隆都能交叉杂交，但限制性内切酶分析和异源双链分析表明，存在2个密切相关的白蛋白mRNA序列。这2种白蛋白mRNA仅有8%的错配，但可通过使用严格杂交条件进行正选择来分离。用这2种纯化的mRNA注射的卵母细胞，将68,000或74,000道尔顿的白蛋白分泌到培养基中，这表明非洲爪蟾血清中的2种白蛋白是由这2个密切相关的mRNA编码的。白蛋白mRNA丰度的测量表明，这2种白蛋白mRNA一起约占雄性非洲爪蟾肝脏总聚腺苷酸加尾RNA的9%，但编码74,000道尔顿mRNA的mRNA丰度约为编码68,000道尔顿mRNA的两倍。
