Uncovering Changes in 3D-Chromatin Structure and Dynamic Gene Expression During Spermatogenesis

Spermatogonial stem cells (SSCs) have the potential for self-renewal and differentiation, and normal spermatogenesis maintains a stable number of spermatogonial stem cells and spermatozoa. Spermatogenesis is accompanied by changes in the three-dimensional structure of chromatin and gene expression, but the structural differences between the stages and the higher-order chromatin dynamics have not yet been elucidated. Consequently, we conducted a high-throughput analysis of the chromatin structural organization and gene expression by using porcine spermatogonia (SPG), spermatocytes (SPY) and round spermatids (RS). We found that during spermatogenesis, SPY showed a weaker pattern of chromosomal interactions, attenuated compartmentalisation, and a reduction in the number of TADs (topological associating domains), which was restored during the subsequent period of round spermatids. These findings suggest reprogramming of higher-order chromatin structures during porcine spermatogonia differentiation. Our results reveal that chromatin structure changes during porcine spermatogenesis, along with changes in gene expression. In conclusion, our study reveals the interrelationships between higher-order chromatin structure and gene expression in spermatogonia, spermatocytes, and round spermatids, providing new insights into the understanding of spermatogenesis as well as basic theoretical data for male reproductive techniques in biological sciences.