Characteristics of the BMP7 Promoter in Hu Sheep

The BMP7 gene is involved in the growth and development of hair follicles but its regulation mechanism is unclear. We studied the regulation mechanism of the BMP7 promoter by cloning the proximal promoter of BMP7 for bioinformatics analysis. A series of missing vectors was then constructed for dual-fluorescein activity detection based on the bioinformatics analysis results. We tested transcription-factor binding-site mutations and transcription factor over-expression to analyze the transcriptional regulation principle of the BMP7 promoter region. The upstream transcriptional regulatory region of the BMP7 gene proximal promoter was predicted by bioinformatics. There were −1216 bp to −1166 bp and −632 bp to −582 bp transcription initiation sites in the upstream transcriptional regulatory region of the BMP7 gene proximal promoter. The CpG islands’ distribution showed that there were many CpG islands at −549 bp to 1 bp. A dual-luciferase assay revealed high activity between −758 bp and −545 bp in the core region and a possible binding site for transcription factors SP1 and EGR1. The transcriptional activity of BMP7 was significantly decreased in the transcriptional regulatory region of the BMP7 after EGR1 and SP1 mutation. Transcription was significantly enhanced by over expression of the EGR1 transcription factor, which strongly suggests that EGR1 and SP1 play important roles in BMP7 regulation.

Transcriptional Regulation of gga-miR-451 by AhR:Arnt in Mycoplasma gallisepticum (HS Strain) Infection

MicroRNAs (miRNAs) have been determined to be important regulators for pathogenic microorganism infection. However, it is largely unclear how miRNAs are triggered during pathogen infection. We previously reported that the up-regulation of gga-miR-451 negatively regulates the Mycoplasma gallisepticum (MG)-induced production of inflammatory cytokines via targeting tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ). The aim of this study was to investigate the mechanism regulating gga-miR-451 in MG infection in chickens. Analysis of gga-miR-451 precursor, pri-miR-451, and pre-miR-451 indicated that the regulation occurred transcriptionally. We also identified the transcriptional regulatory region of gga-miR-451 that contained consensus-binding motif for aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (Arnt) complex, which is known as the transcription factor that regulates gene expression. Luciferase reporter assays combined with chromatin immunoprecipitation (ChIP) demonstrated that AhR:Arnt bound directly to the promoter elements of gga-miR-451, which were responsible for gga-miR-451 transcription in the context of MG infection. Furthermore, upregulation of AhR:Arnt significantly induced gga-miR-451 and inhibited YWHAZ expression, suggesting that AhR:Arnt may play an anti-inflammatory role in MG infection. This discovery suggests that induced gga-miR-451 expression is modulated by AhR:Arnt in response to MG infection.