. "Edited: Matthews, L, 2005-07-26 23:29:22"^^ . "Authored: Matthews, L, Rice, AP, 2005-07-27 00:00:00"^^ . "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)."^^ . . . . . . "2-4 nt.backtracking of Pol II complex on the HIV-1 template leading to elongation pausing"^^ . . .