Analysis of MUTYH alternative transcript expression, promoter function, and the effect of human genetic variants. Issue 4 (24th January 2019)

• Record Type: Journal Article
• Authors: Köger, Nicole; Brieger, Angela; Hinrichsen, Inga M.; Zeuzem, Stefan; Plotz, Guido
• Is Part Of: Human mutation. Volume 40:Issue 4(2019)
• Page Start: 472
• Page End: 482
• Publication Date: 2019-01-24
• Subjects: colorectal cancer -- DNA base excision repair (BER) -- MUTYH‐associated polyposis (MAP) -- MUTYH -- promoter function -- uncertain genetic variant; Human chromosome abnormalities -- Periodicals; Mutation (Biology) -- Periodicals; 616.04205
• DOI: 10.1002/humu.23709
• Languages: English
• ISSNs: 1059-7794

Abstract

Abstract: The human DNA repair gene MUTYH, whose mutational loss causes a colorectal polyposis and cancer predisposition, contains three alternative first exons. In order to analyze alternative transcription and the effect of genetic alterations found in humans, we established a cell‐based minigene experimental model supporting transcription and splicing and thoroughly verified its functionality. We identified highly conserved promoter areas and inactivated them in the minigene, and also introduced six human variants. Moreover, the potential contribution of CpG island methylation and specific transcription factors on MUTYH transcription was addressed. The findings allowed to attribute regulatory roles to three conserved motifs in the promoter: an M4 motif, a transcription factor IIB recognition element, and a GC box. Moreover, the data showed that three patient variants compromised MUTYH expression and therefore have the potential to cause pathogenic effects. We did not find evidence for a biologically relevant contribution of CpG island methylation or a direct transcriptional activation by DNA damage. Besides insight into the regulation of MUTYH transcription, the work therefore provides a functional MUTYH minigene experimental system suitable as a diagnostic tool for analyzing patient variants, and a functional map of the promotor that also can facilitate pathogenicity classifications of human variants. Abstract : The MUTYH gene, which is associated with hereditary colorectal cancer, has a promoter that enables tissue‐dependent formation of alternative transcripts. This promoter was analyzed using a novel minigene model supporting both transcription and splicing, which helped identifying its relevant controlling motifs and assessing the effects of human genetic variants. The work enabled insight into alternative MUTYH transcript expression control and provides a functional map of its promoter.