Generation of retroviruses for the overexpression of cytosolic and mitochondrial glutathione reductase in macrophages in vivo

Construction of a eukaryotic expression plasmid encoding the human PKAR IIβ gene and its expression in human gastric cancer BGC-823 cells

AIM: To construct a eukaryotic expression plasmid encoding the human protein kinase A regulatory subunit II beta (PKAR IIβ) gene and to examine its expression and localization in BGC-823 gastric cells using green fluorescent protein as a reporter.

METHODS: The coding sequence of the PKAR IIβ gene was amplified from the plasmid pRSETB-PKARIIβ by PCR and subcloned into pEGFP-C1 vector after digestion with Xho I and EcoR I. After the identity of recombinant plasmid was verified by direct sequencing, the plasmid was transfected into BGC-823 cells. The expression of the recombinant plasmid in BGC-823 cells was detected by Western blot. The localization of GFP-PKARIIβ in BGC-823 cells was observed by laser scanning confocal microscopy.

RESULTS: The coding sequence of the PKARIIβ gene was inserted into the pEGFP-C1 vector successfully. Restriction enzymes digestion showed that the length of the insert was 1.2 kb, matching the expected size. The expression of GFP-PKARIIβ fusion protein, which had a molecular weight of 72 000 Da, was detected in BGC-823 cells by Western blot. The GFP-PKARIIβ protein was localized predominantly to the cytoplasm but sparsely to the nucleus of HEK293 and BGC-823 cells.

CONCLUSION: A recombinant plasmid expressing the PKARIIβ gene has been successfully constructed and provides a tool for future investigation of PKARIIβ functions. The GFP-PKARIIβ fusion protein was expressed mainly in the cytoplasm of HEK293 and BGC7901 cells.

Construction of pEGFP-restin recombinant plasmid and its expression in BGC-803 gastric cancer cells

AIM: To construct a vector containing human restin gene and observe its expression in gastric cancer cells BGC-803 with green fluorescence protein as the reporter gene.

METHODS: Restin gene was amplified from mRNA of fetal kidney tissue by RT-PCR. The RT-PCR products and pEGFP-C1 were simultaneously digested, then purified, ligated, and transformed to construct the recombinant vector pEGFP-restin. Then the recombinant pEGFP-restin was transfected into gastric cancer cells BGC-803. The expression of green fluorescence protein was observed by fluorescence microscopy, and Western blot was used to examine the expression of target protein.

RESULTS: Agarose gel elctrophrosis showed a 600-bp band of the RT-PCR product, which matched the expected size. Through digestion, the inserted DNA sequence was confirmed to be the premature gene of restin, which was ligated to pEGFP-C1 and transfected into BGC-803 cells successfully. The strong expression of green fluorescence protein was observed by fluorescence microscopy, and the expression of target protein was identified using Western blot.

CONCLUSION: The recombinant vector pEGFP-restin is successfully constructed, providing important subject for further investigation of restin function.