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Polycomb complex protein BMI-1 also known as polycomb group RING finger protein 4 (PCGF4) or RING finger protein 51 (RNF51) is a protein that in humans is encoded by the ''BMI1'' gene (B cell-specific Moloney murine leukemia virus integration site 1).〔 BMI1 is a polycomb ring finger oncogene. == Function == BMI1 (B lymphoma Mo-MLV insertion region 1 homolog) has been reported as an oncogene by regulating p16 and p19, which are cell cycle inhibitor genes. Bmi1 knockout in mice results in defects in hematopoiesis, skeletal patterning, neurological functions, and development of the cerebellum. Recently it has been reported BMI1 is rapidly recruited to sites of DNA damage and it sustains for over than 8h. Loss of BMI1 leads to radiation sensitive and impaired repair of DNA double-strand breaks by homologous recombination 10. Bmi1 is necessary for efficient self-renewing cell divisions of adult hematopoietic stem cells as well as adult peripheral and central nervous system neural stem cells. However, it is less important for the generation of differentiated progeny. Given that phenotypic changes in Bmi1 knockout mice are numerous and that Bmi1 has very broad tissue distribution, it is possible that it regulates the self-renewal of other types of somatic stem cells. Bmi1 is also thought to inhibit ageing in neurons through the suppression of p53. The Bmi-1 expression interacts with several signaling containing Wnt, Akt, Notch, Hedgehog and receptor tyrosine kinase (RTK) pathway. In Ewing sarcoma family of tumors (ESFT), the knockdown of BMI-1 gene would greatly influence the Notch and Wnt signaling pathway which are important for ESFT formation and development. Bmi-1 was shown to mediate the effect of Hedgehog signaling pathway on mammary stem cell proliferation. Bmi-1 also regulates multiple downstream factors or genes. It represses p19Arf and p16Ink4a. Bmi-1-/- neural stem cells and HSCs have high expression level of p19Arf and p16Ink4a which diminished the proliferation rate. Bmi-1 is also indicated as a key factor in controlling Th2 cell differentiation and development by stabilizing GATA transcription factors. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「BMI1」の詳細全文を読む スポンサード リンク
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