2-4 nt.backtracking of Pol II complex on the HIV-1 template leading to elongation pausing

Pol II pausing is believed to result from reversible backtracking of the Pol II enzyme complex by ~2 to 4 nucleotides. This leads to misaligned 3'-OH terminus that is unable to be an acceptor for the incoming NTPs in synthesis of next phosphodiester bond (reviewed by Shilatifard et al., 2003).

多聚酶II的暂停现象被认为是由于多聚酶II酶复合物以可逆的方式回溯约2至4个核苷酸所致。这导致3'-OH末端错位，无法作为合成下一个磷酸二酯键时接受NTP的受体（参见Shilatifard等人的综述，2003年）。