Inhibition of early steps of HIV-1 replication by SNF5/Ini1.
To replicate, human immunodeficiency virus, type 1 (HIV-1) needs to integrate a cDNA copy of its RNA genome into a chromosome of the host cell, a step controlled by the viral integrase (IN) protein. Viral integration involves the participation of several cellular proteins. SNF5/Ini1, a subunit of the SWI/SNF chromatin remodeling complex, was the first cofactor identified to interact with IN. We report here that SNF5/Ini1 interferes with early steps of HIV-1 replication. Inhibition of SNF5/Ini1 expression by RNA interference increases HIV-1 replication. Using quantitative PCR, we show that both the 2-long terminal repeat circle and integrated DNA forms accumulate upon SNF5/Ini1 knock down. By yeast two-hybrid assay, we screened a library of HIV-1 IN random mutants obtained by PCR random mutagenesis using SNF5/Ini1 as prey. Two different mutants of interaction, IN E69G and IN K71R, were impaired for SNF5/Ini1 interaction. The E69G substitution completely abolished integrase catalytic activity, leading to a replication-defective virus. On the contrary, IN K71R retained in vitro integrase activity. K71R substitution stimulates viral replication and results in higher infectious titers. Taken together, these results suggest that, by interacting with IN, SNF5/Ini1 interferes with early steps of HIV-1 infection.
Maroun
Marlène
M
Institut Cochin, Département Maladies Infectieuses, F-75014 Paris, Inserm, U567, F-75014 Paris, France.
Delelis
Olivier
O
Coadou
Gaël
G
Bader
Thomas
T
Ségéral
Emmanuel
E
Mbemba
Gladys
G
Petit
Caroline
C
Sonigo
Pierre
P
Rain
Jean-Christophe
JC
Mouscadet
Jean-François
JF
Benarous
Richard
R
Emiliani
Stéphane
S
D002384:Catalysis; D049109:Cell Proliferation; D002868:Chromosomal Proteins, Non-Histone; D004247:DNA / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000502:physiology*; D015497:HIV-1 / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D011485:Protein Binding; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D011995:Recombination, Genetic; D000071796:SMARCB1 Protein; D014157:Transcription Factors / Q000502:physiology*; D020798:Two-Hybrid System Techniques; D014779:Virus Replication
D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors; D004247:DNA