Upstream regulatory elements of murine alpha 4-interferon gene confer inducibility and cell type-restricted expression.
Upstream regulatory elements of murine alpha 4-interferon gene confer inducibility and cell type-restricted expression.
复制标题
DOI：
10.1016/s0021-9258(18)60442-9
复制
发表时间：
1989-07
期刊：
影响因子：
--
通讯作者：
N. Raj;R. Israeli;M. Kellum;P. Pitha
中科院分区：
文献类型：
--
作者：
N. Raj;R. Israeli;M. Kellum;P. Pitha
我们已经鉴定出了小鼠α4-干扰素基因的诱导型和细胞限制性表达所需的DNA序列，并对其进行了功能表征。将α 4启动子区或其5′端缺失插入CAT基因上游，构建了杂交质粒，并在小鼠L细胞中进行了永久和瞬时表达试验，结果基本一致。诱导表达不受-109缺失的影响;然而，当缺失延伸到-96时，纽卡斯尔病病毒的诱导被消除;然而，该杂交质粒组成型表达。进一步删除到-88不允许组成型或诱导型表达。从最小α 4或人类免疫缺陷病毒启动子区的α 4启动子区5′插入35个碱基对长的序列（−109至−75个碱基对），赋予这两个失活启动子诱导作用。5′端缺失的杂合体或含有诱导元件的质粒在不有效表达内源性α 4基因的NIH/3 T3细胞中仅以低水平被诱导，表明诱导区也决定细胞特异性表达。AGTGAA的串联重复序列以两个拷贝存在于α 4的−109至−88区域，在L细胞中表现出基础水平的表达和诱导，而其类似物AATGAA具有高度诱导性，但不组成性表达。合成六聚体重复序列的诱导未显示细胞类型限制性表达，表明其反应未完全反映诱导区和内源性α基因观察到的表达范围。
We have identified and functionally characterized DNA sequences that are required for the inducible and cell-restricted expression of the murine α4-interferon gene. Hybrid plasmids in which the α4promoter region or its 5′ deletions were inserted upstream of the CAT gene were constructed, and the expression of these hybrid genes was studied in mouse L-cells both in permanent and transient assays with comparable results. Inducible expression was not affected by deletions up to −109; however, when the deletion was extended to −96, inducibility by Newcastle disease virus was abolished; however, this hybrid plasmid was expressed constitutively. Further deletion to −88 did not permit either constitutive or inducible expression. Insertion of the 35-base pair-long sequence (−109 to −75 base pairs) from the α4promoter region 5′ of the minimal α4or human immunodeficiency virus promoter region, conferred inducibility to these two inactive promoters. The 5′ deleted hybrids or plasmids containing the inducible element were induced only at low levels in transfected NIH/3T3 cells that do not express endogenous α4gene efficiently, indicating that the inducible region also determines the cell-specific expression. A tandem repeat of AGTGAA, which is present in the −109 to −88 region of α4in two copies, showed both basal levels of expression and inducibility in L-cells, while its analogue AATGAA was highly inducible but was not expressed constitutively. The inducibility of the synthetic hexamer repeats did not show cell type-restricted expression, suggesting that their response does not fully reflect the range of expression observed for the inducible region and the endogenous α genes.