Dhundale A, Lampson B, Furuichi T, Inouye M, Inouye S
Department of Biochemistry, Robert Wood Johnson Medical School at Rutgers, University of Medicine and Dentistry of New Jersey, Piscataway 08854.
Cell. 1987 Dec 24;51(6):1105-12. doi: 10.1016/0092-8674(87)90596-4.
The branched RNA (msdRNA) of M. xanthus consists of 77 bases. The 20th rG residue is linked to the 5' end of msDNA, consisting of 162 bases, by a 2', 5' phosphodiester linkage. The msdRNA coding region is located on the chromosome in the opposite orientation to the msDNA coding region, with the 3' ends overlapping by eight bases. S1 nuclease mapping experiments indicate that the primary product of msdRNA is much longer at both the 5' and 3' ends (approximately 375 bases). Because of homologous sequences upstream of the msdRNA and msDNA coding regions, the precursor RNA molecule is considered to form an extremely stable stem-and-loop structure (delta G = -210 kcal). We propose a novel mechanism of DNA synthesis in which the stem-and-loop structure serves as a primer as well as a template to form the branched RNA-linked msDNA.
黄色粘球菌的分支RNA（msdRNA）由77个碱基组成。第20个rG残基通过2'，5'-磷酸二酯键与由162个碱基组成的msDNA的5'末端相连。msdRNA编码区位于染色体上，其方向与msDNA编码区相反，3'末端有8个碱基重叠。S1核酸酶图谱实验表明，msdRNA的初级产物在5'和3'末端都长得多（约375个碱基）。由于msdRNA和msDNA编码区上游存在同源序列，前体RNA分子被认为形成了一个极其稳定的茎环结构（ΔG = -210千卡）。我们提出了一种新的DNA合成机制，其中茎环结构既作为引物又作为模板来形成分支RNA连接的msDNA。
