Construction and analysis of deletion mutations in the pol gene of moloney murine leukemia virus: A new viral function required for productive infection

Human immunodeficiency virus integration protein expressed in Escherichia coli possesses selective DNA cleaving activity.

“…A substantially reduced level of cleavage was observed with an HIV U5 substrate in which the C in the conserved CA dinucleotide was replaced with a T. Surprisingly, a similar change in the DNA sequence of a murine leukemia virus resulted in only a slight reduction in the level of the 3'-recessed viral DNA precursor in infected cells and in the rate of replication compared with the wildtype virus (22 The role of the retroviral IN in this process has not been fully elucidated. Genetic evidence suggests that IN is required for integration (1)(2)(3). Furthermore, in cells infected with murine leukemia viruses, functional IN is required for the formation of the 3'-recessed linear DNA molecule that is the probable immediate precursor to the integrated form of the DNA (21,22).…”

“…The insertion event depends on at least one viral protein, the integration protein (IN), which is a product of the viral pol gene. Mutations in the IN coding region ofpol result in integration-negative, replication-defective retroviruses (1)(2)(3). The proviral DNA is identical to the precursor viral DNA except for the loss of two base pairs (bp) at each end, at the points of attachment to cellular DNA.…”

A recombinant retrovirus carrying a non-producer human immunodeficiency virus (HIV) type 1 variant induces resistance to superinfecting HIV

“…Similar results were obtained after the recombinant retroviral infection of human or murine cell lines, such as HeLa or N I H 3T3 (data not shown). This suggests that unknown mutation(s) in the integrase sequences and/or function, which occurred in either the F12/HIV genome or in the strain of pLj retroviral vector used (Donehower & Varmus, 1984;Schwartzberg et al, 1984), may account for its inability to integrate into the host genome. This episomal viral D N A showed a remarkable stability over a > 2 year time interval (Fig.…”

Multifunctional facets of retrovirus integrase

“…The retrovirus IN was first identified and purified from an alpharetrovirus [1] and genetically shown to be necessary for integration [2][3][4][5] . The avian retrovirus or Rous sarcoma virus (RSV) and HIV IN proteins are 286 and 288 residues in length, respectively, while the prototype foamy virus (PFV) IN is 392 residues [6] (Figure 2 …”