bims-nucpor 2023-10-22 papers

Issue of 2023‒10‒22
two papers selected by
Sara Mingu, Johannes Gutenberg University

Commun Biol. 2023 Oct 18. 6(1): 1033

Nucleoporin downregulation modulates progenitor differentiation independent of nuclear pore numbers.

Amy E Neely, Yang Zhang, Laura A Blumensaadt, Hongjing Mao, Benjamin Brenner, Cheng Sun, Hao F Zhang, Xiaomin Bao.

Nucleoporins (NUPs) comprise nuclear pore complexes, gateways for nucleocytoplasmic transport. As primary human keratinocytes switch from the progenitor state towards differentiation, most NUPs are strongly downregulated, with NUP93 being the most downregulated NUP in this process. To determine if this NUP downregulation is accompanied by a reduction in nuclear pore numbers, we leveraged Stochastic Optical Reconstruction Microscopy. No significant changes in nuclear pore numbers were detected using three independent NUP antibodies; however, NUP reduction in other subcellular compartments such as the cytoplasm was identified. To investigate how NUP reduction influences keratinocyte differentiation, we knocked down NUP93 in keratinocytes in the progenitor-state culture condition. NUP93 knockdown diminished keratinocytes' clonogenicity and epidermal regenerative capacity, without drastically affecting nuclear pore numbers or permeability. Using transcriptome profiling, we identified that NUP93 knockdown induces differentiation genes related to both mechanical and immune barrier functions, including the activation of known NF-κB target genes. Consistently, keratinocytes with NUP93 knockdown exhibited increased nuclear localization of the NF-κB p65/p50 transcription factors, and increased NF-κB reporter activity. Taken together, these findings highlight the gene regulatory roles contributed by differential NUP expression levels in keratinocyte differentiation, independent of nuclear pore numbers.

DOI: https://doi.org/10.1038/s42003-023-05398-6

J Exp Bot. 2023 Oct 18. pii: erad396. [Epub ahead of print]

Nucleoporin 50 proteins affect longevity and salinity stress tolerance in seeds.

Ayumi Oishi, Shitomi Nakagawa, Kentaro Tamura.

Nucleoporin 50 (Nup50) is an evolutionarily conserved protein that is a constituent of the nuclear pore complex (NPC); however, its physiological role in plants is unclear. Arabidopsis has two Nup50 proteins, Nup50a and Nup50b, which are highly expressed in developing seeds. GFP-fused Nup50a and Nup50b are localized exclusively in the nucleopolasm, implying an additional function beyond the NPC in the nuclear envelope. To investigate the function of Nup50s, we employed the CRISPR/Cas9 system to generate a nup50a nup50b double mutant, which exhibited premature translation termination of both Nup50 proteins. While the mutant showed no significant abnormal phenotype during vegetative growth, the nup50a nup50b seeds had an abnormal shape compared to wild type. Comparative transcriptomics using immature seeds revealed that Nup50s regulate the expression of various genes, including cell-wall-related genes. The nup50a nup50b seeds exhibited reduced seed longevity and salinity-stress tolerance. Tetrazolium uptake and mucilage release assays implied that the nup50a nup50b seeds had greater water permeability than the wild type. Taken together, our results imply that Nup50s play a critical role in seed formation by regulating gene expression.

Keywords: Arabidopsis thaliana ; Nup50; gene expression; salinity stress; seed formation; seed longevity; transcriptome

DOI: https://doi.org/10.1093/jxb/erad396