[Cloning of ID4 gene expression regulation promoter and subcloning of recombinant ID4 promoter luciferase reporter].

UNLABELLED: The present study was aimed to clone ID4 gene promoter and upstream regulatory region, and to construct a series of recombinant promoter-luciferase reporter for exploring the mechanism of ID4 gene expression regulation. METHODS AND RESULTS: the upstream 5' flanking sequence of 2242 bp from transcriptional start site (TSS) and downstream 5' non-coding region of 212 bp on ID4 gene were searched out and downloaded from human genome databank of NCBI using whole length of ID4 gene cDNA as a probe; On-line promoter analysis softwares, including TESS and Genomax, were employed to analyze the characteristics of ID4 gene promoter and upstream regulatory elements. Then, based on the analytic results, PCR primers were designed and synthesized. Segmental amplification method was adopted to obtain two fragments of 1829 bp and 784 bp. The two fragments were inserted into the plasmid pGEM-T, transformed into TOP10 competent E. coli., and positive recombinants were screened respectively. Subsequently, restriction enzymes KpnI/NheI and KpnI/EcoRI were used to digest the above-mentioned two plasmids pGEM-T and pGL3, and ligation was completed by T4 DNA ligase. After transformation to TOP10 competent E. coli. and screening of positive colonies, the basic recombinant ID4 gene promoter-pGL3 was successfully constructed. KpnI/NheI double digestion and sequencing showed that the target fragment was 2 459 bp and consistent with the corresponding sequence of GenBank; Using the 2459 bp fragment as a template, 5 pairs of primers with identical 3' terminus and different 5' terminus were designed and synthesized for half-nest PCR amplification. 5 fragments with an interval of approximate 400 bp each other, i.e. 2112 bp, 1703 bp, 1290 bp, 784 bp and 496 bp, were produced and inserted into pGEM-T after recovery and purification for transformation to TOP10 competent E. coli. and screening of positive colonies. After that, KpnI/NheI was used to digest the above-mentioned five pGEM-T recombinant plasmids and pGL3 basic vector, and the ligation was completed by T4 DNA ligase. After transformation to TOP10 competent E. coli. and screening for positive colonies, 5 subcloned recombinants of ID4 gene promoter and pGL3 Basic vector cells were constructed. In conclusion, 2.5 kb ID4 gene promoter with upstream expression regulatory sequence was successfully cloned and a series of ID4 promoter subclone-pGL3-Basic recombinant were constructed for further researches on activity, expression regulation and function of ID4 promoter.