open access

Vol 57, No 2 (2019)
Original paper
Submitted: 2019-01-02
Accepted: 2019-04-12
Published online: 2019-05-20
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L1-ORF1p and Ago2 are involved in a siRNA-mediated regulation for promoter activity of L1-5’UTR

Liu Shi12, Huanhuan Shi1, Liangliang Lou1, Xiaoning Yuan1, Yunfeng Zhu1
·
Pubmed: 31112282
·
Folia Histochem Cytobiol 2019;57(2):56-63.
Affiliations
  1. College of Life Sciences and Bio-engineering, Beijing Jiaotong University, Beijing 100044, China
  2. Department of Psychiatry, University of Oxford, OX3 7JX, UK

open access

Vol 57, No 2 (2019)
ORIGINAL PAPERS
Submitted: 2019-01-02
Accepted: 2019-04-12
Published online: 2019-05-20

Abstract

Introduction. Long interspersed nuclear elements-1 (L1), as the only one self-active retrotransposon of the mobile element, was found to be generally activated in tumor cells. The 5‘UTR of L1 (L1-5’UTR) contains both sense and antisense bidirectional promoters, transcription products of which can generate double-strand RNA (dsRNA). In addition, L1-ORF1p, a dsRNA binding protein encoded by L1, is considered to engage in some RNA-protein (RNP) formation. Ago2, one of the RISC components, can bind to dsRNA to form RISC complex, but its role in L1 regulation still remains unclear. Due that the 5‘UTR of L1 (L1-5’UTR) contains both sense and antisense bidirectional promoters, so the activities in both string were identified. A dsRNA-mediated regulation of L1-5’UTR, with the feedback regulation of L1-ORF1p as well as other key molecules engaged (Ago1–4) in this process, was also investigated.

Material and methods. Genomic DNA was extracted from HEK293 cells and subjected to L1-5’UTR prepa­ration by PCR. Report gene system pIRESneo with SV40 promoter was employed. The promoter activities of different regions in L1-5’UTR were identified by constructing these regions into pIRESneo, which SV40 region was removed prior, to generate different recombinant plasmids. The promoter activities in recombinant plasmids were detected by the luciferase expression assay. Western blot and co-immunoprecipitation were employed to identify proteins expression and protein-protein interaction respectively.

Results. Ago2 is a member of Agos family, which usually forms a RISC complex with si/miRNA and is involved in post- transcriptional regulation of many genes. Here L1-ORF1p and Ago2 conducts a regulation as a negative feedback for L1-5'UTR sense promoter. L1-ORF1p could form the immune complexes with Ago1, Ago2 and Ago4, respectively.

Conclusions. L1-5’UTR harbors both sense and antisense promoter activity and a dsRNA-mediated regulation is responsible for L1-5’UTR regulation. Agos proteins and L1-ORF1p were engaged in this process.

Abstract

Introduction. Long interspersed nuclear elements-1 (L1), as the only one self-active retrotransposon of the mobile element, was found to be generally activated in tumor cells. The 5‘UTR of L1 (L1-5’UTR) contains both sense and antisense bidirectional promoters, transcription products of which can generate double-strand RNA (dsRNA). In addition, L1-ORF1p, a dsRNA binding protein encoded by L1, is considered to engage in some RNA-protein (RNP) formation. Ago2, one of the RISC components, can bind to dsRNA to form RISC complex, but its role in L1 regulation still remains unclear. Due that the 5‘UTR of L1 (L1-5’UTR) contains both sense and antisense bidirectional promoters, so the activities in both string were identified. A dsRNA-mediated regulation of L1-5’UTR, with the feedback regulation of L1-ORF1p as well as other key molecules engaged (Ago1–4) in this process, was also investigated.

Material and methods. Genomic DNA was extracted from HEK293 cells and subjected to L1-5’UTR prepa­ration by PCR. Report gene system pIRESneo with SV40 promoter was employed. The promoter activities of different regions in L1-5’UTR were identified by constructing these regions into pIRESneo, which SV40 region was removed prior, to generate different recombinant plasmids. The promoter activities in recombinant plasmids were detected by the luciferase expression assay. Western blot and co-immunoprecipitation were employed to identify proteins expression and protein-protein interaction respectively.

Results. Ago2 is a member of Agos family, which usually forms a RISC complex with si/miRNA and is involved in post- transcriptional regulation of many genes. Here L1-ORF1p and Ago2 conducts a regulation as a negative feedback for L1-5'UTR sense promoter. L1-ORF1p could form the immune complexes with Ago1, Ago2 and Ago4, respectively.

Conclusions. L1-5’UTR harbors both sense and antisense promoter activity and a dsRNA-mediated regulation is responsible for L1-5’UTR regulation. Agos proteins and L1-ORF1p were engaged in this process.

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Keywords

L1-5’UTR; Ago2; L1-ORF1p; antisense promoter; siRNA; HEK293 cells; protein interactions

About this article
Title

L1-ORF1p and Ago2 are involved in a siRNA-mediated regulation for promoter activity of L1-5’UTR

Journal

Folia Histochemica et Cytobiologica

Issue

Vol 57, No 2 (2019)

Article type

Original paper

Pages

56-63

Published online

2019-05-20

Page views

2064

Article views/downloads

1091

DOI

10.5603/FHC.a2019.0006

Pubmed

31112282

Bibliographic record

Folia Histochem Cytobiol 2019;57(2):56-63.

Keywords

L1-5’UTR
Ago2
L1-ORF1p
antisense promoter
siRNA
HEK293 cells
protein interactions

Authors

Liu Shi
Huanhuan Shi
Liangliang Lou
Xiaoning Yuan
Yunfeng Zhu

References (21)
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