Nucleoporin 54 contributes to homologous recombination repair and post-replicative DNA integrity

Abstract

The nuclear pore complex (NPC) machinery is emerging as an important determinant in the maintenance of genome integrity and sensitivity to DNA double-strand break (DSB)-inducing agents, such as ionising radiation (IR). In this study, using a high-throughput siRNA screen, we identified the central channel NPC protein Nup54, and concomitantly its molecular partners Nup62 and Nup58, as novel factors implicated in radiosensitivity. Nup54 depletion caused an increase in cell death by mitotic catastrophe after IR, and specifically enhanced both the duration of the G2 arrest and the radiosensitivity of cells that contained replicated DNA at the time of IR exposure. Nup54-depleted cells also exhibited increased formation of chromosome aberrations arisen from replicated DNA. Interestingly, we found that Nup54 is epistatic with the homologous recombination (HR) factor Rad51. Moreover, using specific DNA damage repair reporters, we observed a decreased HR repair activity upon Nup54 knockdown. In agreement with a role in HR repair, we also demonstrated a decreased formation of HR-linked DNA synthesis foci and sister chromatid exchanges after IR in cells depleted of Nup54. Our study reveals a novel role for Nup54 in the response to IR and the maintenance of HR-mediated genome integrity.

Nucleoporin Nup58 localizes to centrosomes and mid-bodies during mitosis

“…S4). This result is in line with a study by Rodriguez-Berriguete et al [39] reporting that knockdown of Nup58 does not impair nuclear import. Furthermore, we found that centrosomal abnormalities were increased three-fold compared with control siRNA mitotic cells (n = 500 mitotic cells).…”

Qualitative Differences Between the IFNα subtypes and IFNβ Influence Chronic Mucosal HIV-1 Pathogenesis

“…(2) SMAD4, a key regulator of TGFβ [70], which in turn promotes mucosal barrier integrity ( Fig 9F); (3) VIMP and SEP15, selenoproteins that regulate protein folding in the endoplasmic reticulum [71,72] that were linked to anti-inflammatory processes [72]; and (4) two co-factors of HIV-1 Vpr, NUP54 and MUS81 [56,73]. NUP54 is a nuclear pore component and MUS81 is an endonuclease; both are involved in maintaining genomic DNA integrity [74,75]. percentages (Figs 8 and 9G).…”

Acetylation of Nup62 by TIP60 ensures accurate chromosome segregation in mitosis

“…Having demonstrated an enzymatic association between TIP60 and Nup62, we sought to determine the functional relevance of Nup62 during mitosis using live cell imaging of HeLa cells expressing GFP-Nup62 and GFP-Nup62 ΔCC . To systematically assess the function of Nup62 in faithful mitotic progression, we employed a siRNA to suppress endogenous Nup62 ( Supplementary Figure S4A and B ) based on published work ( Rodriguez-Berriguete et al, 2018 ). Importantly, suppression of Nup62 resulted in loss of nuclear rims in significant population of asynchronous cells depleted of Nup62 by siRNA ( Supplementary Figure S4C and D ).…”

“…All the plasmids constructed were immediately sequenced for verification. The sense strand sequence of the siRNA was as follow: 5′-GCAAGAUCCUCAAUGCGCA-3′ ( Rodriguez-Berriguete et al, 2018 ). Cells expressing TIP60 shRNA were established by using lentivirus-based system as previously described ( Mo et al, 2016 ).…”