Swergold G D
Laboratory of Biochemistry, National Cancer Institute, Bethesda, Maryland 20892.
Mol Cell Biol. 1990 Dec;10(12):6718-29. doi: 10.1128/mcb.10.12.6718-6729.1990.
A constructed human LINE-1 (L1Hs) element containing intact 5' and 3' untranslatable regions and an in-frame fusion between the L1Hs open reading frame 1 and the bacterial lacZ gene (p1LZ) was found to promote the expression of beta-galactosidase in a variety of transiently transfected cell types in tissue culture. Full-length RNA was detected in the transfected cells. Most of the RNA transcripts initiated at or near the beginning of the L1Hs segment. Sequences within the L1Hs segment of p1LZ were sufficient for expression of the reporter gene; however, modulation of the transcriptional regulatory region by upstream sequences was not ruled out. Deletion analysis revealed that the sequences most critical for transcription were located within the first 100 bp of L1Hs. Other sequences within the first 668 bp of L1Hs also contributed to overall expression. Expression of p1LZ was high in human teratocarcinoma cells and low in all other cell types. This pattern of cell-type-specific expression matches the known pattern of endogenous L1Hs transcription in cultured cells.
一个构建的人类LINE-1（L1Hs）元件，包含完整的5'和3'非翻译区，以及L1Hs开放阅读框1与细菌lacZ基因之间的读框内融合（p1LZ），被发现可促进组织培养中多种瞬时转染细胞类型中β-半乳糖苷酶的表达。在转染细胞中检测到全长RNA。大多数RNA转录本在L1Hs片段的起始处或附近起始。p1LZ的L1Hs片段内的序列足以驱动报告基因的表达；然而，不排除上游序列对转录调控区的调节作用。缺失分析表明，对转录最关键的序列位于L1Hs的前100 bp内。L1Hs前668 bp内的其他序列也对整体表达有贡献。p1LZ在人畸胎瘤细胞中的表达较高，而在所有其他细胞类型中的表达较低。这种细胞类型特异性表达模式与培养细胞中内源性L1Hs转录的已知模式相匹配。
