Effect of BCL11A gene on transcription of γ-globin gene / 中国实验血液学杂志

This study was aimed to explore the effect of BCL11A gene on transcription of γ-globin gene in K562 cells. B-cell lymphoma/leukemia 11A (BCL11A) gene was silenced by small interfering RNA (siRNA) expression vectors in K562 cells (human erythroblastic leukemia cell line). Gamma-globin mRNA level in K562 cells was determined by RT-PCR. Association between the BCL11A gene and γ-globin gene transcription was explored by comparison of mRNA levels. The results indicated that the silence rate of the BCL11A gene in K562 cells by 4 siRNA expression vectors was 49.7%, 55.4%, 78.2%, and 84.1%, respectively. The siRNA expression vector with 84.1% silence rate was transfected into K562 cells, transcription level of γ-globin mRNA in K562 cells transfected with siRNA expression vector increased 2.4 times as compared with control K562 cells. It is concluded that level of γ-globin mRNA increases when the BCL11A gene is silenced. It indicates that the BCL11A gene may be a negative regulator for γ-globin gene expression.

Different splice of the calpain 3 gene in human skeletal muscle tissue and white blood cells / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the splice variants of the calpain 3 gene existing in human skeletal muscle tissue and white blood cells, and to explore the feasibility of gene diagnosis using CAPN3 mRNA extracted from peripheral leukocytes.</p><p><b>METHODS</b>Total RNA was extracted from peripheral blood and skeletal muscle tissue in healthy individuals. CAPN3 cDNAs were determined by reverse transcriptase polymerase chain reaction and DNA sequencing. CAPN3 cDNAs from peripheral leukocytes were compared with sequences obtained from skeletal muscle tissue.</p><p><b>RESULTS</b>RT-PCR and DNA sequencing showed that the CAPN3 cDNAs comprised 24 exons in human skeletal muscle tissue, while the number of exons was 23 in white blood cells. Exon 15 was spliced out in human white blood cells.</p><p><b>CONCLUSION</b>Splice variants exist in human skeletal muscle tissue and white blood cells. Gene diagnosis may omit the mutations of exon 15 using mRNA extracted from peripheral leukocytes. These findings suggest that mutation analysis of the CAPN3 cDNA should use skeletal muscle tissue as materials instead of peripheral blood.</p>

Hypoxia/reoxygenation-induced increased activity and expression of PTP-1B in neonatal rat cardiomyocytes are mediated by nitric oxide / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore if the hypoxia/reoxygenation-induced increased activity and expression of PTP-1B in neonatal rat cardiomyocytes are mediated by nitric oxide (NO).</p><p><b>METHODS</b>Neonatal rat cardiomyocytes were isolated and randomly divided into 4 groups: normal group (N group); hypoxia/reoxygenation group (H/R group); N(omega)-nitro-l-arginine methylester treated group (L-NAME group); hypoxia/reoxygenation plus L-NAME group (L-NA + H/R group). PTP-1B activity in cardiomyocytes was determined spectrophotometrically at 405 nm, PTP-1B expression in cardiomyocytes was detected by Western blot.NO and LDH concentrations in cell medium were also assayed.</p><p><b>RESULTS</b>PTP-1B activity and expression in cardiomyocytes was significantly higher in the H/R group as compared to the N group and this increase could be blocked by cotreatment with L-NAME. As compared to H/R group, nitric oxide and LDH concentrations in cell medium were significantly decreased in the L-NA + H/R group (NO concentration: H/R group, 368% +/- 13% and L-NA + H/R group, 61% +/- 7%, P < 0.005; LDH concentration: H/R group, 41.2 +/- 6.7 and L-NA + H/R group, 23.6 +/- 4.8, P < 0.05).</p><p><b>CONCLUSIONS</b>This study showed that pretreatment with L-NAME, a non-selective inhibitor of NOS, prevented the hypoxia/reoxygenation-induced increase in PTP-1B activity and expression in cardiomyocytes, suggesting PTP-1B activation during hypoxia/reoxygenation was mediated by nitric oxide.</p>