%0 Journal Article
%T APOBEC3G encapsidation into HIV-1 virions: which RNA is it?
%A Klaus Strebel
%A Mohammad A Khan
%J Retrovirology
%D 2008
%I BioMed Central
%R 10.1186/1742-4690-5-55
%X APOBEC3G is a cytidine deaminase that was recently identified as the prime substrate of the HIV-1 viral infectivity factor Vif [1]. In the absence of Vif, APOBEC3G is packaged into viral cores and potently interferes with virus replication (for a recent review see [2]). While it is undisputed that much of APOBEC3G's antiviral activity comes from its encapsidation into virions, the mechanism of APOBEC3G packaging remains under discussion. Several studies conclude that APOBEC3G packaging is RNA independent and mediated by an APOBEC3G:Gag interaction while others identified a requirement for viral or cellular RNA in the APOBEC3G packaging process (Figure 1).The study by Bach et al. [3] attempts to shed light onto the mechanism of APOBEC3G packaging. As far as the requirement of NC for packaging of 7SL RNA is concerned, the authors' data are in good agreement with a previous report by Wang et al. [4] showing that deletion of NC reduced packaging of 7SL RNA. Bach et al. disagree, however, with two other reports who found no significant NC-dependence for 7SL packaging [5,6]. Thus, the vote is tied at 2:2 on this issue. As far as the requirement of 7SL RNA for the packaging of APOBEC3G is concerned, Bach et al. fail to observe a correlation between APOBEC3G packaging and 7SL RNA incorporation. They therefore side with Khan et al. who previously also failed to see such a correlation [6]. Thus, the score is 2:1 against an involvement of 7SL RNA in the packaging of APOBEC3G. Unfortunately, Bach et al. did not analyze the importance of genomic RNA for APOBEC3G packaging, an issue on which Wang and Khan disagree. The score on that issue therefore remains tied at 1:1. Svarovskaia et al. also remain neutral on this issue by proposing that incorporation of APOBEC3G into HIV-1 virions involves both viral and nonviral RNAs [7].There clearly is a trend in the field to accept the importance of RNA in the packaging of APOBEC3G into HIV-1 virions. But which RNA is it? There is no simple
%U http://www.retrovirology.com/content/5/1/55