RESUMO
Cohesion is essential for the identification of sister chromatids and for the biorientation of chromosomes until their segregation. Here, we have demonstrated that an RNA-binding motif protein encoded on the X chromosome (RBMX) plays an essential role in chromosome morphogenesis through its association with chromatin, but not with RNA. Depletion of RBMX by RNA interference (RNAi) causes the loss of cohesin from the centromeric regions before anaphase, resulting in premature chromatid separation accompanied by delocalization of the shugoshin complex and outer kinetochore proteins. Cohesion defects caused by RBMX depletion can be detected as early as the G2 phase. Moreover, RBMX associates with the cohesin subunits, Scc1 and Smc3, and with the cohesion regulator, Wapl. RBMX is required for cohesion only in the presence of Wapl, suggesting that RBMX is an inhibitor of Wapl. We propose that RBMX is a cohesion regulator that maintains the proper cohesion of sister chromatids.
Assuntos
Cromátides/fisiologia , Ribonucleoproteínas Nucleares Heterogêneas/fisiologia , Proteínas de Transporte/metabolismo , Proteínas de Transporte/fisiologia , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/fisiologia , Centrômero/metabolismo , Proteoglicanas de Sulfatos de Condroitina/metabolismo , Proteoglicanas de Sulfatos de Condroitina/fisiologia , Cromátides/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Cromossômicas não Histona/fisiologia , Proteínas de Ligação a DNA , Fase G2 , Células HeLa , Ribonucleoproteínas Nucleares Heterogêneas/genética , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo , Humanos , Proteínas Nucleares/metabolismo , Proteínas Nucleares/fisiologia , Fosfoproteínas/metabolismo , Fosfoproteínas/fisiologia , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas/fisiologia , Interferência de RNARESUMO
We compared dentition status and temporomandibular joint (TMJ) disorders in 142 women with rheumatoid arthritis (RA, ages, 40 to 69 years) and 143 women of similar age without RA. The RA group had significantly fewer remaining teeth than the non-RA group. Number of decayed, missing, and filled (DMF) teeth, number of edentulous subjects, and number of subjects with complete and removable partial dentures were significantly higher in the RA group. Among RA subjects, 1.4% had unprovoked TMJ pain, 4.9% had pain on mouth opening, and 14.8% noted difficulty with opening. In the RA group, TMJ tenderness was elicited in 9.2%, clicking in 12.7%, and crepitus in 35.9%, representing a significant excess occurrence of crepitus. The prevalence of TMJ disorders was 67.6% in the RA group and 32.9% in the non-RA group; degenerative joint disorders were particularly frequent. TMJ disorders correlated with Steinbrocker stage and the duration of RA.
