Prokaryotic expression and purification of the cDNA of recombinant human cytokeratin 9

Objective: To clone and fuse the cDNA of human cytokeratin 9 in prokaryotic expression system, and purify and identify the fusion protein. Methods: The cDNA fragment of human cytokeratin 9 was amplified from human keratinocyte (HaCaT) total RNA with specific primers. The PCR products were cloned into vector pET-28a, then the fusion protein of his-CK9 was induced by IPTG. The expressed fusion protein of his-CK9 was purified by nickel ion affinity chromatography and identified by SDS-PAGE and Western blot. Results: The sequencing proved that the recombinant vector of the cDNA of CK9 was correct. The fusion protein of his-CK9 was induced to be expressed in E.coli. The fusion protein of his-CK9 was highly purified and his-CK9 showed specific binding to the commercialized antibodies of CK9. Conclusion: The recombinant vector of pET-28a-CK9 has been successfully constructed, and the fusion protein of his-CK9 has been successfully expressed and purified.