N-myc-dependent repression of Ndr1, a gene identified by direct subtraction of whole mouse embryo cDNAs between wild type and N-myc mutant
N-myc-dependent repression of Ndr1, a gene identified by direct subtraction of whole mouse embryo cDNAs between wild type and N-myc mutant
复制标题
DOI：
10.1016/s0925-4773(99)00025-8
复制
发表时间：
1999-05-01
影响因子：
2.6
通讯作者：
Kondoh, H
中科院分区：
文献类型：
--
作者：
Shimono, A;Okuda, T;Kondoh, H
为了鉴定受N-myc调控的基因，在野生型和N-myc缺陷突变小鼠之间进行全胚胎cDNA的扣除。分离出6个cDNA克隆，作为在突变体胚胎中表达较高的基因，2个作为表达较低的基因。其中之一，Ndr 1，编码43 kDa的胞质蛋白进行了详细研究。在交配后10.5天，Ndr 1基因在突变胚胎中增加了20倍，这表明N-myc的抑制。野生型胚胎各发育组织中himyc和Ndr 1的表达量呈负相关。在这些组织分化的早期阶段，当N-myc表达高时，Ndr 1表达低或检测不到，后来当N-myc活性降低时，Ndr 1表达伴随着终末分化的发生而增加。为了建立N-myc活性与Ndr 1调控之间的直接联系，克隆并分析了Ndr 1基因。N-myc下调Ndr 1启动子活性，而N-myc和Max的联合作用对Ndr 1启动子活性的影响更大。这种抑制作用是介导的启动子区域内的52个碱基对的转录起始位点，但直接结合的N-myc：最大的启动子序列没有被证明，这是类似的情况下，最近报道的转录抑制c-myc。c-myc也抑制Ndr 1启动子活性类似于N-myc。N-myc：Max的作用对曲古抑菌素A敏感，表明组蛋白去乙酰化酶活性参与了Ndr 1启动子的抑制。当突变动物可用时，我们在识别转录因子的靶基因中所采用的策略应该被证明是广泛适用的。(C)1999爱思唯尔科学爱尔兰有限公司保留所有权利。
To identify genes regulated by N-myc, subtraction of whole embryo cDNA was carried out between wild type and N-myc-deficient mutant mice. Six cDNA clones were isolated as representing genes expressed higher in the mutant embryos and two as those expressed lower. One of them, Ndr1, coding for 43 kDa cytoplasmic protein was studied in detail. The Ndr1 gene was augmented 20-fold in the mutant embryos at 10.5 days post coitus which is indicative of repression by N-myc. An inverse relationship actually existed between the expression of hi myc and Ndr1 in various developing tissues of the wild type embryos. In the early stage of differentiation of these tissues when N-myc expression was high Ndr1 expression was low or undetectable, and later when N-myc activity diminished Ndr1 expression was augmented concomitantly with the occurrence of terminal differentiation. To establish the direct link between N-myc activity and the Ndr1 regulation, the Ndr1 gene was cloned and analyzed. The Ndr1 promoter activity was down-regulated by N-myc, and more strongly by the combination of N-myc and Max in the cotransfection assay. This repressive effect was mediated by the promoter region within 52 base pairs from the transcription start site but direct binding of N-myc:Max to the promoter sequence was not demonstrated, which is analogous to the cases recently reported for transcriptional repression by c-myc. c-myc also repressed Ndr1 promoter activity similarly to N-myc. The effect of N-myc:Max was sensitive to Trichostatin A, indicating involvement of histone deacetylase activity in repression of the Ndr1 promoter. The strategy we adopted in identifying target genes of a transcription factor should prove widely applicable when mutant animals are available. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.