Retrovirology Research BioMed Central Open Access Recruitment of HIV-1 envelope occurs subsequent to lipid mixing: a fluorescence microscopic evidence Miao-Ping Chien, Chi-Hui Lin and Ding-Kwo Chang* Address: Institute of Chemistry, Academia Sinica, Taipei, Taiwan 11529, ROC Email: Miao-Ping Chien - michelle@; Chi-Hui Lin - chlin824@; DingKwo Chang* - dkc@ * Corresponding author Published: 2 March 2009 Retrovirology 2009, 6:20 doi: Received: 6 January 2009 Accepted: 2 March 2009 This article is available from: © 2009 Chien et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (), which permits unrestricted use, distribution, and reproduction in any. | Retrovirology BioMed Central Research Recruitment of HIV-1 envelope occurs subsequent to lipid mixing a fluorescence microscopic evidence Miao-Ping Chien Chi-Hui Lin and Ding-Kwo Chang Address Institute of Chemistry Academia Sinica Taipei Taiwan 11529 ROC Email Miao-Ping Chien - michelle@ Chi-Hui Lin - chlin824@ Ding-Kwo Chang - dkc@ Corresponding author Open Access Published 2 March 2009 Received 6 January 2009 Retrovirology 2009 6 20 doi 1742-4690-6-20 Accepted 2 March 2009 This article is available from http content 6 1 20 2009 Chien et al licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract_ Entry of the human immunodeficiency virus HIV into the target cell is initiated by fusion with the cell membrane mediated through the envelope glycoproteins gp 120 and gp41 following engagement to CD4 and the co-receptor. Previous fusion kinetics studies on the HXB2 envelope protein Env revealed that Env recruitment occurred at about 13 min concurrent with the lipid mixing. To resolve the temporal sequence of lipid mixing and recruitment we employed an inhibitory assay monitored by fluorescence microscopy using a gp41 ectodomain gp41 e fragment which blocked Env recruitment in stark contrast to the lack of gp41e effect on the lipid mixing. In addition to demonstrate the mode of action for the inhibition of gp41e our results strongly suggested that lipid mixing precedes the Env recruitment because lipid mixing can proceed with Env recruitment inhibited by exogeneous gp41e molecules. Importantly it was found that the random clustering of Env molecules on the membrane surface .
