Host Proteins in Retroviral DNA Integration

Abstract

Publisher Summary This chapter focuses on host proteins potentially important for another step in the viral life cycle: the integration of retroviral complementary DNA (cDNA) into host DNA. Many host-encoded proteins seem likely to be important for retroviral cDNA integration. Many other host systems are also subverted to support viral replication. Host cell surface proteins act as receptors, and host molecular chaperones direct protein folding. Relatively small viruses, such as retroviruses, encode relatively few proteins and rely on the host to provide many additional functions, such as apparatus for transcription and RNA processing. For the case of human immunodeficiency virus (HIV), several exciting insights have come with the identification of new host factors important for replication. The chapter discusses the host proteins involved in the early steps of cDNA integration and host proteins involved in the late stages of integration reaction. The chapter concludes with proteins influencing target site selection, such as (a) effects of primary sequence in target DNA in vitro , (b) effects of proteins bound to target DNA in vitro , (c) effects of chromosomd proteins on integration in vivo , and (d) target site selection by retrovirus-like Ty transposons of yeast. Candidate proteins have been proposed to stimulate integration, block autointegration, carry out late DNA repair steps, and modulate target site selection. Future studies will need to focus on strengthening the evidence for in vivo importance of each candidate and advancing the understanding of the mechanism.