CENP-U (CENP-50) is a component of the CENP-O complex, which includes CENP-O, CENP-P, CENP-Q, CENP-R, and CENP-U and is constitutively localized at kinetochores throughout the cell cycle in vertebrates. Although CENP-U deficiency results in some mitotic defects in chicken DT40 cells, CENP-U-deficient chicken DT40 cells are viable. To examine the functional roles of CENP-U in an organism-dependent context, we generated CENP-U-deficient mice. The CENP-U-deficient mice died during early embryogenesis (approximately E7.5). Thus, conditional CENP-U-deficient mouse ES cells were generated to analyze CENP-U-deficient phenotypes at the cell level. When CENP-U was disrupted in the mouse ES cells, all CENP-O complex proteins disappeared from kinetochores. In contrast, other kinetochore proteins were recruited in CENP-U-deficient mouse ES cells as CENP-U-deficient DT40 cells. However, the CENP-U-deficient ES cells died after exhibiting abnormal mitotic behavior. Although CENP-U was essential for cell viability during mouse early embryogenesis, CENP-U-deficient mouse embryonic fibroblast cells were viable, similar to the DT40 cells. Thus, although both DT40 and ES cells with CENP-U deficiency have similar mitotic defects, cellular responses to mitotic defects vary among different cell types.
Translational Genetics and Genomics Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health (NIH), Bethesda, Md. Electronic address:
Background: Phospholipase Cγ2 (PLCγ2) is an important signaling molecule that receives and transmits signals from various cell surface receptors in most hematopoietic lineages. Variants of PLCG2 cause PLCγ2-associated immune dysregulation (PLAID), a family of conditions classified by mutational effect. PLAID with cold urticaria (PLAID-CU) is caused by in-frame deletions of PLCG2 that are dominant negative at physiologic temperatures but become spontaneously active at subphysiologic temperatures.
To establish bipolar attachments of microtubules to sister chromatids, an inner kinetochore subcomplex, the constitutive centromere-associated network (CCAN), is assembled on centromeric chromatin and recruits the microtubule-binding subcomplex called the KMN network. Since CCAN proteins CENP-C and CENP-T independently bind to the Mis12 complex (Mis12C) of KMN, it is difficult to evaluate the significance of each interaction in cells. Here, we demonstrate the molecular details of the CENP-T-Mis12C interaction using chicken DT40 cells lacking the CENP-C-Mis12C interaction.
Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan. Electronic address:
A nucleoside analog, Cidofovir (CDV), is used for the treatment of viral diseases such as cytomegalovirus retinitis and herpes virus infection. CDV converts to its active diphosphate metabolite (CDVpp) through cellular kinases and acts as a competitive inhibitor for viral polymerase thereby interfering with viral replication. However, the effect of this drug on the replication of healthy host cells and the mechanisms involved in the cellular tolerance to CDV are yet to be fully understood.
H2A.Z-nucleosomes are present in both euchromatin and heterochromatin and it has proven difficult to interpret their disparate roles in the context of their stability features. Using an in situ assay of nucleosome stability and DT40 cells expressing engineered forms of the histone variant we show that native H2A.
Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1,Hachioji-shi, Tokyo 192-0397, Japan. Electronic address:
Remdesivir is a 1'-cyano-modified adenine nucleotide analog used for the treatment of COVID-19. Recently, the anti-carcinogenic effect of remdesivir has been also identified in human cancers. However, the impact of this drug and the mechanisms underlying the cellular tolerance to remdesivir have not been elucidated.
