A New Model about the Role of Satellite DNA in Forming Higher-Order Chromatin Structure

Wheat ( Triticum aestivum L.) is riched with repetitive sequences. Researchers have used repetitive sequences and fluorescence in situ hybridization (FISH) techniques to study the chromosomal structure variation and systematic evolution of Triticeae. It is well known that repetitive sequences play an important role in maintaining chromosome structure. However, only a few studies have focused on how repetitive sequences form higher-order chromatin structures. In this study, we analyzed compositions and arrangements of 120 bp family tandem repeats pSc119.2 in wheat chromosome 3B and established a chromatin folding model based on reverse complementary tandem repeats. The model suggested that repeat sequences are arranged in reverse direction could form loops for the purpose of condensing chromatin, thus keeping the metaphase chromosomes stable. These findings contributed to the understanding of the role of repetitive sequences in the higher order structure of chromatin.