G-quadruplex structures and CpG methylation cause drop-out of the maternal allele in polymerase chain reaction amplification of the imprinted MEST gene promoter.

ABSTRACT: We observed apparent non-Mendelian behaviour of alleles when genotyping a region in a CpG island at the 5' end of the maternally imprinted human MEST isoform. This region contains three single nucleotide polymorphisms (SNPs) in total linkage disequilibrium, such that only two haplotypes occur in the human population. Only one haplotype was detectable in each subject, never both, despite the use of multiple primers and several genotyping methods. We observed that this region contains motifs capable of forming several G-quadruplex structures. Circular dichroism spectroscopy and native polyacrylamide gel electrophoresis confirmed that at least three G-quadruplexes form in vitro in the presence of potassium ions, and one of these structures has a Tm of greater than 99°C in polymerase chain rea

SUBMITTER: Stevens AJ 

PROVIDER: S-EPMC4249981 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature