Journal: Viruses
Article Title: Analysis of Factors That Regulate HIV-1 Fusion in Reverse
doi: 10.3390/v17040472
Figure Lengend Snippet: Effects of lipid variations on fusion in reverse infections. ( A ) The HIV-1 viral membrane is highly enriched in cholesterol (CHOL), and has substantial amounts of ceramide (CER). The inner leaflets are enriched for phosphatidylserine (PS), phosphatidylinositol-4,5-bisphosphate (PI[4,5]P2; PIP2), and phosphatidylethanolamine (PE), while the outer leaflet is enriched in sphingomyelin (SM), hexosylceramides (HEX), and saturated phosphatidylcholines (PCs). ( B – D ) Infectivities of equivalent volumes of virus were scored via β-gal activities, and were normalized either to untreated (−) samples, or for convenience in the panel ( D ) CD/CX infections, to viruses from CerS−/− cells. In all panels, CD/CX viruses refer to lentivirus vectors generated by co-transfection of 293 cells with a GagPol expression vector (psPAX2), a β-gal-transducing vector (pLVX-puro-Xho-ATG-β-gal), as well as CD4-GPI and CXCR4-318 plasmids. Also, in all panels, Env-WT and Env-753 targets cells refer to 293 cells transfected to express those proteins. For panels ( B , C ), WT and 753 viruses are the NL4-3 variants and were used to infect TZM-bl reporter cells; for panel ( D ), WT refers to viruses produced from cells transfected with psPAX2, pLVX-puro-Xho-ATG-β-gal, plus a WT Env expression vector, while targets were 293 cells transfected to express the CD4-GPI and CXCR4-318 proteins. In panel ( B ), AME refers to treatment of viruses with 10 mM AME prior to infections. In panel ( C ), TMEM refers to co-transfection of virus producing cells with (+) or without (−) the mTMEM-GY scramblase expression vector. In panel ( D ), CerS2−/− pertains to producing viruses either from 293 cells (−) or from 293-CerS2−/− knockout cells (+). For panels ( B – D ), averages and standard deviations are as indicated, noting that where error bars are missing, it is because the standard deviations were too small to be depicted. The following significant differences were obtained by conversion of means and standard deviations to Z values for probability calculations: Panel ( B ) WT/TZMBL, AME −/+, p < 0.001; Panel ( B ) CDCX/Env-WT, AME −/+, p < 0.001; Panel C all pairs p < 0.001; Panel ( D ) CDCX/Env-WT, CerS2−/−, −/+, p < 0.01; all other Panel D pairs, p < 0.001. Note that in panel ( D ), if normalizations were based on CDCX viruses produced from WT 293 cells and infections of Env-753Stop-expressing cells, infectivities of CDCX viruses from virus–cell combinations would be as follows: from WT 293 cells into Env-753Stop cells, 100%; from CerS2−/− cells into Env-753Stop cells 500%; from WT 293 cells into Env-WT cells, 8%; from CerS2−/− cells into Env-WT cells, 19%.
Article Snippet: The employed primary antibodies were as follows: mouse anti-HIV-CA hybridoma media (Hy183, kindly provided by Dr. Bruce Chesebro) at 1:15; mouse anti-gp41(CT) hybridoma media (Chessie 8, recognizing CT residues 727-732 [PDRPEG], from the NIH AIDS Reagent Program) at 1:15; rabbit anti-CD4 D2E6M monoclonal antibody (Cell Signaling Technology, 93518T), used at 1:2000; polyclonal rabbit anti-CXCR4 antibody (ProSci, #1009), used at 1:2000.
Techniques: Membrane, Virus, Generated, Cotransfection, Expressing, Plasmid Preparation, Transfection, Produced, Knock-Out