Andrologia-acesso aberto
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Abstrato

Chromatin Organization and Transcriptional Regulation at TADs and Loops Depleted Pachytene Stage during Spermatogenesis

Zhengyu Luo, Xiaoyuan Song

In mammals, high-order chromatin structures are reorganized during spermatogenesis. Topologically Associating Domains (TADs) and chromatin loops are almost lost at the pachytene stage while CTCF and cohesion are still bound on pachytene chromatin, and the promoters and enhancers on pachytene chromatin remain open. The fact that pachytene chromatin is actively transcribed when TADs and chromatin loops are lost indicates that gene transcriptional regulation at pachytene stage can be independent of TADs and chromatin loops. TADs and chromatin loops loss is also found in CTCF and cohesion acute degraded cells in vitro. In this review, we discuss the reorganized chromatin organization during spermatogenesis, especially at pachytene stage. We also discuss recent progress in our understanding about fine-scale chromatin structures beyond TADs and chromatin loops and their relationship with transcriptional regulation in normal and CTCF or cohesion depleted cells. Finally, we show that recent findings about chromatin structures beyond TADs and chromatin loops may explain the gene transcriptional regulation at pachytene stage.