Funktionelle Untersuchungen zu Krankheits-assoziierten Mutationen in den Genen ABCA4 und VMD2

Corinna Aichinger
Stargardt disease is caused by mutations in the ABCA4 gene, whereas mutations in the VMD2 gene lead to Best disease and ADVIRC (autosomal dominant vitreoretinochoroidpathy). Such mutations can be divided into different classes, e.g. missense, nonsense or splice site mutations. Deletions or insertions, which in some extent involve larger parts of the gene associated with the respective disease, are observed as well. The effect of mutations, particularly on splicing behaviour, can be examined by
more » ... can be examined by the so called exon trapping analysis. The aim of this work is the investigation of disease associated base exchanges in the ABCA4 and VMD2 genes on molecular level by exon trapping analysis, thereby contributing to defining the pathomechanisms of these sequence alterations. The analysis of sequence alterations in the ABCA4 gene shows, that a decisive amount of these actually have an effect on the splicing behaviour of pre-mRNA. Furthermore, the noticed splice site mutations cause a variety of consequences. One of them leads to an out-of-frame deletion with a stop of protein synthesis. Others cause exon skipping and thus, a shift in the reading frame. These results correspond with bioinformatic data on the effects of splice site mutations. The focus of the second part of this project is on the examination of the pathomechanisms of missense mutations in the VMD2 gene. Those sequence alteration are all part of exon 4 of the VMD2 gene. They either cause the phenotype of Best disease or ADVIRC. The results give evidence that the ADVIRC mutation is associated with reduced pre-mRNA splicing, whereas Best mutations rather do not affect the splicing behaviour or even lead to improved splicing. Thus, these results match with those described in literature. It appears to be quite interesting that the experimental splicing behaviour of the VMD2 gene cannot be predicted by bioinformatic data in a reliable way. Using the example of ABCA4 and VMD2 genes, this work investigates the way singular base exchanges in those genes may result in a [...]
doi:10.5283/epub.23604 fatcat:xsbnkm7bafc2xdecjmbkjb3sru