MOLECULAR PATHOGENESIS OF CHROMOSOME 16 INVERSION IN HUMAN LEUKEMIA

人类白血病 16 号染色体倒转的分子发病机制

• 批准号: 2576536
• 负责人: P P LIU
• 金额: --
• 依托单位: NATIONAL HUMAN GENOME RESEARCH INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/2576536
• 关键词: acute myelogenous leukemia; carcinogenesis; chromosome inversion; disease /disorder model; fusion gene; hematopoiesis; human genetic material tag; laboratory mouse; model design /development; molecular oncology; molecular pathology; neoplasm /cancer genetics; oncogenes; protein structure function; transcription factor; transfection; tumor suppressor genes

A pericentric chromosome 16 inversion, inv(16)(p13;q22), is present in almost 100% of patients with the M4Eo subtype of acute myeloid leukemia. A fusion gene between CBFB, the gene for a subunit of transcription factor CBF/PEBP2, and MYH11, which codes for smooth muscle myosin heavy chain, is generated by this chromosome 16 inversion. This fusion gene is believed to play a key role in leukemogenesis. We recapitulated this fusion gene in mice by inserting a human MYH11 cDNA into mouse Cbfb gene by homologous recombination. Chimeric mice lacked contribution of ES cells with the fusion gene to hematopoietic tissues selectively, suggesting a toxic effect of the fusion gene to hematopoiesis. Embryos heterozygous for the fusion gene had defects in both primitive and definitive hematopoiesis and died in midgestation due to widespread CNS hemorrhages. The phenotype is suggestive of a mechanism by which the chimeric protein Cbfb-SMMHC, coded by the fusion gene Cbfb-MYH11, dominantly interferes with transcriptional regulation by CBF as well as one or more additional pathways important for hematopoiesis. The phenotype of hematopoiesis blockage is consistent with the potential of this fusion gene to contribute to leukemogenesis. We are designing experiments to understand the underlying mechanisms and to bypass the embryonic lethality in order to observe the effects of this fusion gene in adult mice. To understand how Cbfb-SMMHC interferes with transcriptional regulation by CBF and other proteins, we have started to analysis its effect on DNA binding by Cbfa and ETS, another transcription factor important for hematopoiesis. Bacterial and insect viral vectors have been constructed or obtained from our collaborator Nancy Speck for the expression of the proteins. Proteins have been purified and used in assays for DNA-protein bindings. Preliminary results indicate that Cbfb-SMMHC has some effect on the cooperative interaction between Cbf and Ets. Further studies are in progress to confirm this finding and to extend to in vivo assays for the detection of any functional differences.

16号染色体臂间倒位inv（16）（p13; q22）存在于 几乎100%的急性髓性白血病M4Eo亚型患者。 CBFB与转录亚基基因之间的融合基因 因子CBF/PEBP 2和MYH 11，其编码平滑肌肌球蛋白重 链，是由16号染色体倒位产生的。这种融合基因是 被认为在白血病发生中起着关键作用。 我们在小鼠中通过插入人MYH 11 cDNA来重现该融合基因， 通过同源重组导入小鼠Cbfb基因。嵌合小鼠缺乏 融合基因ES细胞对造血组织的贡献 选择性，表明融合基因的毒性作用， 造血融合基因杂合的胚胎具有缺陷， 原始和最终的造血，并在妊娠中期死亡，原因是 导致中枢神经系统广泛受损表型暗示了一种机制 该融合基因编码的嵌合蛋白Cbfb-SMMHC Cbfb-MYH11，主要干扰CBF的转录调控 以及一个或多个对造血重要的额外途径。 造血阻滞的表型与潜能相符 这种融合基因的突变导致了白血病的发生我们正在设计 实验，以了解潜在的机制，并绕过 胚胎致死率，以观察该融合基因的作用 在成年小鼠中。 了解Cbfb-SMMHC如何干扰转录调控 通过CBF和其他蛋白质，我们已经开始分析它对DNA的影响， 通过Cbfa和ETS结合，另一种对 造血细菌和昆虫病毒载体已经构建 或者从我们的合作者南希·斯派克那里获得的， proteins.蛋白质已被纯化并用于DNA-蛋白质分析。 绑定。初步结果表明，Cbfb-SMMHC具有一定的作用 Cbf和Ets之间的合作互动。进一步的研究 正在进行中以证实这一发现，并扩展到体内测定， 任何功能差异的检测。