Functional analysis of the promoter of the molt-inhibiting hormone (mih) gene in mud crab Scylla paramamosain

In this study, the 5′-flanking region of molt-inhibiting hormone (MIH) gene was cloned by Tail-PCR. It is 2024 bp starting from the translation initiation site, and 1818 bp starting from the predicted transcription start site. Forecast analysis results by the bioinformatics software showed that the transcription start site is located at 207 bp upstream of the start codon ATG, and TATA box is located at 240 bp upstream of the start codon ATG. Potential transcription factor binding sites include Sp1, NF-1, Oct-1, Sox-2, RAP1, and so on. There are two CpG islands, located at −25- +183 bp and −1451- −1316 bp respectively. The transfection results of luciferase reporter constructs showed that the core promoter region was located in the fragment −308 bp to −26 bp. NF-kappaB and RAP1 were essential for mih basal transcriptional activity. There are three kinds of polymorphism CA in the 5′-flanking sequence, and they can influence mih promoter activity. These findings provide a genetic foundation of the further research of mih transcription regulation.