Li Yajuan, Wei Huilan, Dai Xiaoting, Zhang Lijing, Liu Liangjie, Chen Xiaomei, Liu Tian, Shu Ya, Yang Yaxin, Wang Shi, Bao Zhenmin, Zhang Lingling
Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China.
MOE Key Laboratory of Marine Genetics and Breeding, Laboratory for Marine Biology and Biotechnology (Qingdao Marine Science and Technology Center), Ocean University of China, Qingdao, China.
BMC Genomics. 2025 Jan 24;26(1):69. doi: 10.1186/s12864-025-11266-w.
Spermatogenesis is a complex process of cellular differentiation that commences with the division of spermatogonia stem cells, ultimately resulting in the production of functional spermatozoa. However, a substantial gap remains in our understanding of the molecular mechanisms and key driver genes that underpin this process, particularly in invertebrates. The dwarf surfclam (Mulinia lateralis) is considered an optimal bivalve model due to its relatively short generation time and ease of breeding in laboratory settings.
In this study, over 4,600 testicular cells from various samples were employed to identify single-cell heterogeneity on a more comprehensive scale. The four germ cell populations (spermatogonia, primary spermatocytes, secondary spermatocytes, and round spermatids/spermatozoa) and three somatic populations (follicle cell, hemocyte, and nerve cell) were characterized. The four types of germ cells exhibited disparate cell cycle statuses and an uninterrupted developmental trajectory, progressing from spermatogonia to spermatids/spermatozoa. Pseudotime analysis indicates that gene expression, translation, ATP metabolic process, and microtubule-based process are involved in the transition of germ cell types. Weighted gene coexpression network analysis (WGCNA) identified four modules corresponding to the four types of germ cells, as well as key transcription factors (e.g., MYC, SREBF1, SOXH) that may play a critical role in these cell types. Furthermore, our findings revealed that there is extensive bidirectional communication between the somatic cells and the germline cells, including the FGF and TGF-β signaling pathways, as well as other ligand-receptor pairs, such as NTN1-NEO1 and PLG-PLGRKT.
This study provides a comprehensive single-cell transcriptome landscape of the gonad, which will contribute to the understanding of germ cell fate transition during spermatogenesis, and the development of germ cell manipulation technologies in mollusks.
精子发生是一个复杂的细胞分化过程，始于精原干细胞的分裂，最终产生功能性精子。然而，我们对支撑这一过程的分子机制和关键驱动基因的理解仍存在很大差距，尤其是在无脊椎动物中。矮滨蛤（Mulinia lateralis）因其相对较短的世代时间和易于在实验室环境中繁殖，被认为是一种理想的双壳贝类模型。
在本研究中，使用来自各种样本的超过4600个睾丸细胞，在更全面的规模上识别单细胞异质性。对四个生殖细胞群体（精原细胞、初级精母细胞、次级精母细胞和圆形精子细胞/精子）和三个体细胞群体（卵泡细胞、血细胞和神经细胞）进行了表征。这四种类型的生殖细胞表现出不同的细胞周期状态和不间断的发育轨迹，从精原细胞发展到精子细胞/精子。伪时间分析表明，基因表达、翻译、ATP代谢过程和基于微管的过程参与了生殖细胞类型的转变。加权基因共表达网络分析（WGCNA）确定了与四种生殖细胞类型相对应的四个模块，以及可能在这些细胞类型中起关键作用的关键转录因子（如MYC、SREBF1、SOXH）。此外，我们的研究结果表明，体细胞和生殖系细胞之间存在广泛的双向通讯，包括FGF和TGF-β信号通路，以及其他配体-受体对，如NTN1-NEO1和PLG-PLGRKT。
本研究提供了性腺的全面单细胞转录组图谱，这将有助于理解精子发生过程中生殖细胞命运的转变，以及软体动物生殖细胞操纵技术的发展。
