title: [Different effects on reporter gene expression by distinct L1-ORF2 segements].
abstract: An intact L1 define element is 6 kb in length in human genome. The majority of the L1s is truncated and has direction difference, implying that it is interesting to study the effects of different length and directions of L1s on gene. In this work, 7 different segments were obtained from L1-open reading frame 2 (ORF2), each of which was 280 bp in length. Each segment was connected into 8 repeats in head and tail tandem manner and was inserted to downstream of GFP gene in different directions in pEGFP-C1. The inserted ORF2 segments in the sense orientation caused much stronger inhibition on gene transcription and protein expression than antisense sequences did. Among all segments, the first and ninth 280 bp segments of ORF2 in both orientations induced weaker inhibition on gene transcription than other segments in the same orientations and did not induce transcriptional elongation. The distribution of Alu in most regions of genome was inverse ratio with L1. The inserted Alus in both orientations inhibited GFP gene expression, but the inhibition in antisense orientation was stronger than that in sense orientation and the sense Alu was the sequence of inducing transcription elongation. A-rich of ORF2 was probably the molecular basis of its sense orientation with stronger inhibition on gene expression.
authors.affiliation: Hebei Key Lab of Laboratory Animal, Department of Genetics, Hebei Medical University, Shijiazhuang 050017, China. duanduanxiatian@126.com
authors.forename: Xiao-Cui
authors.initials: XC
authors.lastname: Duan
authors.forename: Xia
authors.initials: X
authors.lastname: Jin
authors.forename: Ying
authors.initials: Y
authors.lastname: Xie
authors.forename: Ning
authors.initials: N
authors.lastname: Jiao
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Wang
authors.forename: Zhan-Jun
authors.initials: ZJ
authors.lastname: Lu
mesh_terms: D015152:Blotting, Northern; D005786:Gene Expression Regulation; D017930:Genes, Reporter / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D016366:Open Reading Frames / Q000235:genetics*; D016133:Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000235:genetics*; D014162:Transfection
chemical_list: D049452:Green Fluorescent Proteins