POSITIONAL CLONING OF THE MEN1 GENE

多发性内分泌瘤1型（MEN1）的特征是多个 甲状旁腺、垂体前叶和胃肠道内分泌组织的肿瘤。 我们之前已经证明MEN1基因的突变是导致 MEN1综合征MEN1编码的核蛋白Menin， 结合转录因子JunD和NF κ B，并可抑制JunD， NFkB诱导的转录。通过在对menin和JunD无效的小鼠成纤维细胞系中表达WT或突变型JunD，我们发现与menin的相互作用是JunD的生长抑制功能所必需的。我们开发了传统的和 条件性小鼠基因敲除模型，其产生的表型 与人类MEN1疾病非常相似，并使我们能够 描绘肿瘤发展的阶段。另外我们有 开发了组织特异性脑膜炎诱导型转基因小鼠模型。 与menin在细胞系和肿瘤发生过程中的存在或不存在相关的表达变化，以及与menin相关的基因的启动子的具体鉴定，正在研究以了解menin的生物学。menin在ES细胞分化为胰岛和造血谱系中的作用正在探索中。此外，MEN1的组织特异性转基因表达和敲除模型正在果蝇中开发。这些模型应该有助于理解menin的功能作用，并提出可能的治疗方向。

Multiple endocrine neoplasia type 1 (MEN1) is characterized by multiple tumors of the parathyroid, anterior pituitary and GI endocrine tissues. We have shown earlier that mutations in the MEN1 gene are responsible for the MEN1 syndrome. The MEN1 encoded nuclear protein, Menin, binds the transcription factors JunD and NFkB, and can repress JunD and NFkB-induced transcription. By expressing WT or mutant JunD in mouse fibroblast cell lines that are null for menin and JunD, we find that interaction with menin is required for the growth suppressor function(s) of JunD. We have developed both conventional and conditional mouse knockout models, which yield phenotypes that are remarkably similar to the human MEN1 disease, and have allowed us to delineate the stages in tumor development. In addition, we have developed tissue specific menin-inducible transgenic mouse models. Expression changes associated with presence or absence of menin in cell lines and during tumorigenesis, and specifically identification of the promoters of the genes with which menin is associated, are being studied to understand the biology of menin. The role of menin in differentiation of ES cells to pancreatic islet and hematopoietic lineages is being explored. In addition, tissue specific transgenic expression and knockout models for MEN1 are being developed in Drosophila. These models should help to understand the functional role(s) of menin and suggest possible therapeutic directions.