基于家畜ESCs创制克隆动物的挑战与展望OA

Livestock embryonic stem cells(ESCs),which possess unlimited self-renewal capacity and multidirectional differentiation potential,are considered important cellular foundations for cloning precise genetic improvement,and germplasm resource conservation.In recent years,with the development of somatic cell nuclear transfer(SCNT)and gene-editing technologies,the application value of livestock ESCs in animal breeding biotechnology has continued to increase.However,due to species-specific differences in embryonic development patterns and pluripotency regulatory mechanisms between livestock and model animals,livestock ESCs still face several challenges,including low establishment efficiency,difficulty in maintaining pluripotency,and incomplete reprogramming,which greatly restrict their application in SCNT.Studies have shown that livestock ESCs are prone to spontaneous differentiation,and resulting in genetic instability,and different pluripotent states can significantly affect the developmental potential of reconstructed embryos after nuclear transfer.Meanwhile,abnormal histone modifications and insufficient DNA methylation reprogramming during SCNT can lead to disordered embryonic gene expression,which are considered major causes of low cloning efficiency and embryonic developmental failure.Compared with somatic donor cells,ESCs exhibit a lower degree of differentiation and a more open chromatin state,providing certain advantages for improving nuclear reprogramming efficiency.In addition,the emergence of induced pluripotent stem cells and other novel stem cell types has provided new technological avenues for the generation of cloned animals and cell-based genome editing.Based on recent advances in livestock ESCs and SCNT research,this review focuses on key issues including ESC establishment and pluripotency maintenance,epigenetic reprogramming regulation,and ESC-mediated cloned animal production.Furthermore,future perspectives on the establishment of functional ESC systems,precise epigenetic regulation,and the combined application of stem cell and gene-editing technologies are discussed,with the aim of providing references for improving livestock cloning efficiency and promoting the development of animal breeding biotechnology.