[PubMed] [CrossRef] [Google Scholar] 68

[PubMed] [CrossRef] [Google Scholar] 68. that remain associated with the preintegration complex (PIC) during and after nuclear translocation is still enigmatic. In this study, we analyzed the progressive organizational changes of viral CA proteins within the cytoplasm and the nucleus by immunogold labeling. Furthermore, we set Csf2 up a novel technology, HIV-1 ANCHOR, which enables the specific detection of the retrotranscribed DNA by fluorescence microscopy, thereby offering the opportunity to uncover the architecture of the potential HIV-1 PIC. Thus, we combined the immunoelectron microscopy and ANCHOR technologies to reveal the presence of DNA- and CA-positive complexes by correlated light and electron microscopy (CLEM). During and after nuclear translocation, HIV-1 appears as a complex of viral DNA decorated by multiple viral CA proteins remodeled in a pearl necklace-like shape. Thus, we could describe how CA proteins are reshaped around the viral DNA to permit the entrance of the HIV-1 in the nucleus. This particular CA protein complex composed of the integrase and the retrotranscribed DNA leads the HIV-1 genome inside the host nucleus. Our findings contribute to the understanding of the early steps of HIV-1 infection and provide new insights into the organization of HIV-1 CA proteins during and after viral nuclear entry. Of note, we are now able to visualize the viral DNA in viral complexes, opening up new perspectives for future studies on viruss fate in the cell nucleus. IMPORTANCE How the reverse-transcribed genome reaches the host nucleus remains a main open question related to the infectious cycle of HIV-1. The HIV-1 core has a size of 100?nm, largely exceeding that of the NPC channel (39?nm). Thus, a rearrangement of the viral CA protein organization is required to Nateglinide (Starlix) achieve an effective nuclear translocation. The mechanism of this process remains undefined due to the lack of a technology capable of visualizing potential CA subcomplexes in association with the viral DNA in the nucleus of HIV-1-infected cells. By the means of state-of-the-art Nateglinide (Starlix) technologies (HIV-1 ANCHOR system combined with CLEM), our study shows that remodeled viral complexes retain multiple CA proteins but not an intact core or only a single CA monomer. These viral CA complexes associated with the retrotranscribed DNA can be observed inside the nucleus, and they represent a potential PIC. Thus, our study shed light on critical early steps characterizing HIV-1 infection, thereby revealing novel, therapeutically exploitable points of intervention. Furthermore, we developed and provided a powerful tool enabling direct, specific, and high-resolution visualization of intracellular and intranuclear HIV-1 subviral structures. and MX2 (9, 10). Furthermore, the viral CA seems to participate in two critical steps of the HIV-1 life cycle, nuclear translocation (4,C7, 17) and integration (18,C23). The viral core is considered fragile (24) and can exist only an intact or completely unbundled structure. However, a recent study highlighted the possibility that partial cores can be stabilized by host factors (25). Thus, HIV-1 CA can exist in different forms in infected cells: as intact cores, as monomers, pentamers, or hexamers, and probably as partial cores. Of note, the viral primary largely exceeds the scale (11,C13) from the nuclear pore route (26); hence, the primary should disassemble before getting into the nucleus. The immediate-uncoating model, which postulates an entire lack of Nateglinide (Starlix) the viral CA proteins (2), continues to be the most certified model before, supported with the impossibility to copurify viral CA with various other viral proteins at early period points because of its hereditary fragility (24, 27). As opposed to this model, Dismuke and Aiken (20) had been the first ever to propose a job for CA in post-nuclear entrance steps, accompanied by various other research (21,C23, 28). Nevertheless, the viral CA proteins was biochemically discovered for the very first time in the nucleus of macrophages and HeLa cells by Zhou and co-workers (23). The current presence of CA in the nucleus was proven also with the analysis of specific time factors of an infection in set cells using surrogate infections or by.