HIV-1 viral cores enter the nucleus collectively through the nuclear endocytosis-like pathway

It is recognized that HIV-1 capsid cores are disassembled in the cytoplasm, releasing their genomes into the nucleus through nuclear pores, but there is also evidence showing the capsid(CA) exists in the nucleus. Whether HIV-1 enters the nucleus and how it enters the nucleus through the undersized nuclear pore remains mysterious. Based on multicolor labeling and real-time imaging of the viral and cellular components, our observations via light and electron microscopy suggest that HIV-1 selectively gathered at the microtubule organization center(MTOC), leading the nearby nuclear envelope(NE) to undergo deformation,invagination and restoration to form a nuclear vesicle in which the viral particles were wrapped;then, the inner membrane of the nuclear vesicle ruptured to release HIV-1 into the nucleus. This unexpected discovery expands our understanding of the complexity of HIV-1 nuclear entry, which may provide new insights to HIV-1 virology.