Dimeric vector was constructed from pUC 18 and pUC 19 for more simplified and efficient cDNA cloning. This system has characteristics which are: 1) vector itself serves as primer for cDNA synthesis, 2) Sl nuclease treatment is not required, 3) vector-primer and linkers are rapidly and reliably prepared. With RNA size fractionation, this system will accomplish a efficient and simplified cDNA cloning system of bovine liver mRNA.
Bovine liver mRNA was prepared from fresh liver tissues and proved to have good translational activity. Prothrombin-specific mRNA was identified in the bovine liver mRNA preparation by Northern blot hybridization with $^{32}p$-oligo-nucleotide containing a segment of complementary sequences of prothrombin mRNA sequences.
PUC 18 과 PUC 19 plasmid 를 두가지의 제한 효소로 절단하고 연결시킴으로서 두 벡터가 혼성된 dimeric DNA를 얻었다. 이것은 3'-protruding end 를 내게되는 제한효소로 자르고 (dT)를 그 끝에 붙이면 cDNA 합성에 있어서 vector-primer로 작용하게 되며, dG-tailed 된 PUC 7 과 더불어 간단하면서도 효과적인 cDNA cloning 을 가능하게 한다.
소의 간에서 mRNA 를 분리하여 이 mRNA 에서 혈액 응고 작용에서의 한 인자인 prothrombin 을 나타내는 유전자를 확인하였으며, 또한 그 mRNA 의 translational activity 도 조사되었다.
