A MITE insertion into the 3′-UTR regulates the transcription of TaHSP16.9 in common wheat

Miniature inverted-repeat transposable elements (MITEs) are a type of DNA transposon frequently inserted into promoters, untranslated regions (UTR), introns, or coding sequences of genes. We found a 276-bp tourist-like MITE insertion in the 3′-UTR of a 16.9 kDa small heat shock protein gene (TaHSP16.9-3A) on chromosome 3A of common wheat. Haplotype analysis revealed two haplotypes, sHSP-W (wild type without MITE insertion) and sHSP-M (mutant with MITE insertion), present in wheat germplasm. Both semiquantitative PCR and quantitative real-time PCR analyses showed increased transcription levels of TaHSP16.9-3A in sHSP-M compared with those of sHSP-W after heat treatment at 42 °C. It appeared that the MITE insertion into the 3′-UTR enhances the transcription of TaHSP16.9-3A.