RESUMO
The La protein is an essential RNA-binding protein implicated in different aspects of RNA metabolism. Herein, we report that small interfering (siRNA)-mediated La depletion reduces cell proliferation of different cell lines concomitant with a reduction in cyclin D1 (CCND1) protein. To exclude off-target effects we demonstrate that exogenous La expression in La-depleted cells restores cell proliferation and CCND1 protein levels. In contrast, proliferation of immortalized CCND1 knockout cells is not affected by La depletion, supporting a functional coherence between La, CCND1 and proliferation. Furthermore, we document by reversible in vivo crosslinking and ribonucleoprotein (RNP) immunoprecipitation an association of the La protein with CCND1 messengerRNA and that CCND1 internal ribosome entry site (IRES)-dependent translation is modulated by La protein level within the cell. In addition, we show elevated La protein expression in cervical cancer tissue and its correlation with aberrant CCND1 protein levels in cervical tumor tissue lysates. In conclusion, this study establishes a role of La in cell proliferation and CCND1 expression and demonstrates for the first time an overexpression of the RNA-binding protein La in solid tumors.
Assuntos
Autoantígenos/metabolismo , Carcinoma de Células Escamosas/metabolismo , Ciclina D1/biossíntese , Ribonucleoproteínas/metabolismo , Neoplasias do Colo do Útero/metabolismo , Autoantígenos/genética , Western Blotting , Carcinoma de Células Escamosas/genética , Proliferação de Células , Separação Celular , Feminino , Citometria de Fluxo , Expressão Gênica , Técnicas de Inativação de Genes , Células HeLa , Humanos , Imuno-Histoquímica , Imunoprecipitação , RNA Interferente Pequeno , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ribonucleoproteínas/genética , Análise Serial de Tecidos , Neoplasias do Colo do Útero/genética , Antígeno SS-BRESUMO
Damage of the lingual nerve is one of the most common problems in oral surgery, especially during removal of the third molar. After microsurgery of the lingual nerve, there is a lack of regeneration of the gustatory fibers in comparison with the sensory fibers. The histologic investigation of ten human lingual nerve preparations showed that the chorda tympani fibers distribute widely in the fascicles of the lingual nerve. Therefore, after microsurgical reconstruction of the lingual nerve in the third molar region, the chance of the gustatory fibers meeting and regenerating is very low.
