Harrison G P, Mayo M S, Hunter E, Lever A M
Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA.
Nucleic Acids Res. 1998 Jul 15;26(14):3433-42. doi: 10.1093/nar/26.14.3433.
In the most extensive examination to date of the relationship between the pausing of reverse transcrip-tase (RT) and RNA secondary structures, pause events were found to be correlated to inverted repeats both ahead of, and behind the catalytic site in vitro. In addition pausing events were strongly associated with polyadenosine sequences and to a lesser degree diadenosines and monoadenosine residues. Pausing was also inversely proportional to the potential bond strength between the nascent strand and the template at the point of termination, for both mono and dinucleotides. A run of five adenosine and four uridine residues caused most pausing on the HIV-1 template, a region which is the site of much sequence heterogeneity in HIV-1. We propose that homopolyadenosine tracts can act as termination signals for RT in the context of inverted repeats as they do for certain RNA polymerases.
在迄今为止对逆转录酶（RT）暂停与RNA二级结构之间关系进行的最广泛研究中，发现体外催化位点之前和之后的暂停事件均与反向重复序列相关。此外，暂停事件与聚腺苷酸序列密切相关，与二腺苷和单腺苷残基的相关性较小。对于单核苷酸和二核苷酸，在终止点处，暂停也与新生链和模板之间的潜在键强度成反比。连续五个腺苷和四个尿苷残基在HIV-1模板上导致了大部分暂停，该区域是HIV-1中许多序列异质性的位点。我们提出，同聚腺苷酸序列在反向重复序列的背景下可作为RT的终止信号，就像它们对某些RNA聚合酶所起的作用一样。
