[SP1 identified as a transcription factor of miR-122-5p].

OBJECTIVE: To study the transcription factors of the spermatogenesis-related promoter mir-122-5p. METHODS: SP1 and GATA4 were predicted as the possible transcription factors of the mir-122-5p promoter by bioinformatics analysis, followed by construction of the double luciferase pGL3-mir-122-5p promoter vector, pcDNA3.1 (+) -SP1 expression vector and pcDNA3.1 (+) -GATA4 expression vector, respectively. The pcDNA-SP1+pGL3-basic mixture plasmid and pcDNA-SP1+ pGL3-miR-122-5p promoter mixture plasmid, pcDNA-GATA4+pGL3-basic mixture plasmid and pcDNA-GATA4+pGL3-miR-122-5p promoter mixture plasmid were transferred into 293T cells. The enzyme activity was detected the Dual-Luciferase Reporter Assay System. RESULTS: The fluorescence value of the pcDNA3.1+pGL3-miR-122 promoter was 0.0362 ± 0.0004, significantly higher than that of the pcDNA3.1+pGL3-basic group (P < 0.05), indicating the successful construction of the mouse miR-122-5p promoter luciferase reporter plasmid. The fluorescence value was markedly higher in the pcDNA -SP1 + pGL3-miR-122-5p promoter than in the pcDNA -SP1+pGL3-basic group, suggesting that the transcription factor SP1 could promote the transcription of miR-122. There was no statistically significant difference in the fluorescence value between the pcDNA -gata4+pGL3-basic transfection and pcDNA -GATA4+pGL3-miR-122-5p promoter transfection groups, indicative of the inability of GATA4 to promote the transcription of miR-122-5p. CONCLUSIONS: The transcription factor SP1, rather than GATA4, can promote the transcription of miR-122-5p.

[Construction of RNA interfering lentiviral vector of occludin and its role in tight junctions].

OBJECTIVE: To investigate the role of occludin in tight junction (TJ) in vitro. METHODS: We constructed RNA interfering lentiviral vectors and transfected them into TM4 cells. Then we detected their inhibitory effect on occuldin by RT-PCR and Western blot and analyzed the role of occuldin in TJ using an in vitro TJ cell model. RESULTS: The pLenti 6.3-EGFP-occludin-miR expression vector was successfully constructed. The results of RT-PCR and Western blot showed that pLenti 6.3-EGFP-occludin-miR-3 significantly inhibited the expression of occludin (P < 0.05), which was remarkably lower than in the blank control and the pLenti 6.3- EGFP transfection group (0.7534 ± 0.089 vs 1.000 and 1.056 ± 0.025, P < 0.05). The expression of occludin was markedly suppressed and the tightness of tight junctions decreased in the TM4 cells transfected with pLenti 6.3-EGFP-occludin-miR-3. CONCLUSIONS: The pLenti 6.3-EGFP-occludin-miR expression vector was successfully constructed, and occludin is one of the functional proteins that maintain tight junctions.