RESUMO
Objective To build an efficient random short hairpin RNA(shRNA)library. Methods shRNA expression vector was constructed with enhanced green fluorescent protein(EGFP)in the upstream of shRNA,driven by pol Ⅱ promoter(CMV).After the constructs were transfected into cells,the proteins were collected.The inhibition efficiency of shRNA was determined by Western blot and dual luciferase reporter system.After the shRNA expression vector was constructed with EGFP in the upstream of shRNA,driven by pol Ⅱ promoter(CMV),shRNA was further embedded into microRNA(miRNA)context.The constructs were transfected into cells,and then the inhibition efficiency of shRNA against target genes was evaluated by quantificational real-time polymerase chain reaction.According to the result of quantificational real-time polymerase chain reaction,a new random shRNA library was constructed based on miRNA context. Results shRNA downstream of a large transcript was transcripted efficiently by pol Ⅱ promoter(CMV).The efficiency of shRNA interference on target gene was improved when shRNA was embedded into miRNA context.Thus,we constructed a new random shRNA library sized 1.8×10based on miRNA context.Conclusion We successfully constructed a new large random shRNA library.
RESUMO
<p><b>OBJECTIVE</b>To investigate the role of TXNDC5 in serum starvation-induced proliferation inhibition of HeLa cell.</p><p><b>METHODS</b>TXNDC5 was either over-expressed or knocked down by small interfering RNA (siRNA) in HeLa cells which were then cultured in conventional medium or serum starvation medium. The protein level of TXNDC5 was evaluated by Western blot analysis. The mRNA level of TXNDC5 was measured by quantitative real-time PCR. Cell growth rate was determined by cell proliferation assay kit (MTS method). Cell cycle distribution and apoptosis were detected by flow cytometry.</p><p><b>RESULTS</b>Serum starvation mildly reduced the mRNA level of TXNDC5 (P<0.05), but dramatically increased the protein level of TXNDC5 in HeLa cells. The stability of TXNDC5 mRNA remained unchanged. Cycloheximide abolished the serum starvation-induced up-regulation of TXNDC5 protein. Over-expression of TXNDC5 had no effect on cell proliferation. However, suppression of TXNDC5 attenuated the proliferation inhibition of HeLa cell induced by serum starvation (P<0.05), increased the proportion of cells in S phase (P<0.05), but had no effect on cell apoptosis.</p><p><b>CONCLUSION</b>TXNDC5 mediates serum starvation-induced proliferation inhibition of HeLa cell.</p>