Investigation of an 11 bp deletion in the Bbs7 promoter on the transcription and its impact on Berlin fat mouse obese phenotype

Background and Aims Berlin Fat Mouse Inbred (BFMI) line has higher body fat mass compared to C57BL / 6N mice. Mapping, using an advanced intercross line, revealed the Bardet Biedl syndrome 7 (Bbs7) gene as the most likely candidate gene for the obese phenotype in the BFMI line which is also associated with a reduced expression of Bbs7 in brain, adipose tissue and liver .Sequence comparisons between BFMI and C57BL / 6N showed an 11 bp deletion in the Bbs7 promoter of the BFMI line. We studied the effect of this deletion on the regulation of transcription.

Material and methods Different lengths of BFMI and C57BL / 6N Bbs7 promotor sequence were cloned into dual-luciferase reporter constructs and transfected into HEK cells. The transcription rates of Bbs7 promotor constructs were assessed by comparing the luciferase ratios 48-72 hours post transfection.

Results Several BFMI vector showed a reduced transcription ratio when compared to the C57BL / 6N vector. However, this was not observed in the vectors containing exclusively the 11 bp deletion, but in vectors which included a part of the 5ʹUTR. Two SNPs were identified in this 5ʹUTR region. After testing each of the SNPs separately, only one of the SNPs caused a significant reduction in transcription.

Conclusion The results show that a single SNP in the Bbs7 5ʹUTR region leads to a reduced expression of the dual-luciferase construct in HEK cells and could thereby contribute to the reduced expression of Bbs7 in BFMI mice.

Publikationsverlauf

Artikel online veröffentlicht:
06. Mai 2021