Non-covalent and reversible interactions with FG domains from multiple Nups and diffusion through the NPC, whereas interaction with Nup153 might be critical for mediating irreversible and directional exit from the NPC. Interaction with FG-repeats may be mediated indirectly by nuclear transport receptors, such as Mechlorethamine hydrochloride importin 7,, or transportin 3. After exit from the nuclear basket, both Nup98 and Nup153, which shuttle on and off the NPC and have been shown to interact with chromatin,,, might accompany the PIC to its integration site. In particular, Nup98 has been found to localise to the nucleoplasm and participate in chromosomal remodelling and regulation of gene expression. It will be interesting to determine whether Nup98 and/or Nup153 are hijacked by HIV-1 for transport to euchromatin and contribute to specific site selection in expressed genes, since previous work has shown that HIV-1 integrates preferentially within actively transcribed genes. Surprisingly, Nup98 depletion affected HIV-1 and MLV infection equally, but the reduction of MLV infectivity could merely be due to the slight accumulation of cells in G1/S phase that we observed since MLV enters the nucleus during metaphase. Our work demonstrates that a key to the ability of HIV-1 to replicate in non-dividing cells is its capacity to use NPC components for its active transport across the nuclear pore, thus underlining the evolutionary adaptability of HIV-1 to exploit host mechanisms to achieve active nuclear import. Our study suggests a new appealing role for the NPC in HIV-1 infection proposing that the viral nuclear entry step may be important not only for actual translocation, but also for correct subsequent integration as a result of the physical interaction that exists between nuclear pore baskets and the chromatin. The study of the physical and functional interactions between HIV-1 and the NPC not only contributes to our understanding of how other viruses manipulate the nuclear pore but also strengthen our comprehension of lentiviral vectors used for gene transfer protocols, whose active nuclear import is similar to that of HIV-1. From a seed no bigger than that of a cucumber, California’s coastal redwood tree can grow to a height of more than 350 feet. At the same time, aquatic watermeal plants are so small that they resemble specks of cornmeal. The nature of the mechanisms controlling the size and shape of organs is an important but still unanswered question of developmental biology. Two factors determine the size of mature organs: cell number and cell size. A current model for metazoans proposes that cell number and cell size are controlled by distinct proliferation and growth signals that negatively affect each other; when cellular size is increased, cell count is reduced and vice versa. This regulation ensures that induced alterations in cell proliferation are compensated for by changes in cell size, resulting in little net Benzethonium Chloride change in the final organ size. The compensation phenomenon has also been observed in plants �C; however, it is not clear whether the model proposed for metazoans can be directly applied to plants;. First of all, the majority of cell elongation occurs after termination of cell division and, therefore, the actions of proliferation factors and cell expansion factors are separated in time. In addition, some signals, such as auxin, regulate both proliferation and elongation of cells . To understand regulation of organ size and the molecular mechanism of compensation it is essential to know the signaling pathways that control and coordinate cell proliferation and cell elongation. Plant hormones are the most obvious candidates for that role, with cytokinins being implicated in regulation of cell proliferation; and gibberellins, brassinosteroids, and auxin regulating both cell proliferation and cell elongation.