Effect of β‑globin MAR characteristic elements on transgene expression.

The aim of the present study was to investigate the effect of the characteristic elements of matrix attachment region (MAR) on transgene expression. Human β‑globin MAR was obtained by PCR amplification. A splicing MAR fragment containing all the characteristic elements of β‑globin MAR was artificially synthesized and then cloned into the eukaryotic expression vector. Following digestion and sequence identification, we transfected Chinese hamster ovary (CHO) cells with the two vectors, and then screened for the transformation of stable cells. The transgene expression level was analyzed by ELISA, and the copy numbers of the CAT gene were analyzed by real‑time fluorescent quantitative PCR. β‑globin MAR enhanced CAT reporter gene expression by 2.1489‑fold, whereas the β‑globin MAR characteristic elements did not enhance this expression. The real‑time fluorescent quantitative PCR analysis demonstrated that the relative copy numbers of the CAT gene of the β‑globin MAR expression vector were 1.2‑fold higher compared with those of the non‑MAR expression vector. MAR was able to improve the transgene expression level to a certain extent. The MAR characteristic elements did not improve the transgene expression alone. The transgenic expression levels were not linear with the transgene copy number; however, the enhancement of transgenic expression was relative to the increase in the gene copy number.