Yang Liuyang, Liu Mengqin, Zhu Yunzhen, Li Yanan, Pan Tao, Li En, Wu Xiaobing
College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
Anhui Provincial Key Laboratory of Conservation and Exploitation of Biological Resources, Anhui Normal University, Wuhu 241000, China.
Animals (Basel). 2023 Oct 6;13(19):3126. doi: 10.3390/ani13193126.
Crocodilians, which are a kind of animal secondary adaptation to an aquatic environment, their hindlimb can provide the power needed to engage in various life activities, even in low-oxygen water environments. The development of limbs is an important aspect of animal growth and development, as it is closely linked to body movement, support, heat production, and other critical functions. For the Chinese alligator, the hindlimb is one of the main sources of power, and its development and differentiation will directly influence the survival ability in the wild. Furthermore, a better understanding of the hindlimb developmental process will provide data support for the comparative evolutionary and functional genomics of crocodilians. In this study, the expression levels of genes related to hindlimb development in the Chinese alligator embryos during fetal development (on days 29, 35, 41, and 46) were investigated through transcriptome analysis. A total of 1675 differentially expressed genes (DEGs) at different stages were identified by using limma software. These DEGs were then analyzed using weighted correlation network analysis (WGCNA), and 4 gene expression modules and 20 hub genes were identified that were associated with the development of hindlimbs in the Chinese alligator at different periods. The results of GO enrichment and hub gene expression showed that the hindlimb development of the Chinese alligator embryos involves the development of the embryonic structure, nervous system, and hindlimb muscle in the early stage (H29) and the development of metabolic capacity occurs in the later stage (H46). Additionally, the enrichment results showed that the AMPK signaling pathway, calcium signaling pathway, HIF-1 signaling pathway, and neuroactive ligand-receptor interaction are involved in the development of the hindlimb of the Chinese alligator. Among these, the HIF-1 signaling pathway and neuroactive ligand-receptor interaction may be related to the adaptation of Chinese alligators to low-oxygen environments. Additionally, five DEGs (, , , , and ) were randomly selected for qRT-PCR to verify the transcriptome results. It is expected that further research on these genes will help us to better understand the process of embryonic hindlimb development in the Chinese alligator.
鳄目动物是对水生环境进行二次适应的一种动物，它们的后肢能够提供进行各种生命活动所需的力量，即使是在低氧水环境中。肢体的发育是动物生长发育的一个重要方面，因为它与身体运动、支撑、产热及其他关键功能密切相关。对于扬子鳄来说，后肢是主要的动力来源之一，其后肢的发育和分化将直接影响其在野外的生存能力。此外，更好地了解后肢发育过程将为鳄目动物的比较进化和功能基因组学提供数据支持。在本研究中，通过转录组分析研究了扬子鳄胚胎在胎儿发育阶段（第29、35、41和46天）与后肢发育相关基因的表达水平。使用limma软件共鉴定出不同阶段的1675个差异表达基因（DEG）。然后使用加权基因共表达网络分析（WGCNA）对这些DEG进行分析，鉴定出4个基因表达模块和20个枢纽基因，它们与扬子鳄不同时期的后肢发育相关。GO富集和枢纽基因表达结果表明，扬子鳄胚胎的后肢发育在早期（H29）涉及胚胎结构、神经系统和后肢肌肉的发育，而在后期（H46）则出现代谢能力的发育。此外，富集结果表明，AMPK信号通路、钙信号通路、HIF-1信号通路和神经活性配体-受体相互作用参与了扬子鳄后肢的发育。其中，HIF-1信号通路和神经活性配体-受体相互作用可能与扬子鳄对低氧环境的适应有关。此外，随机选择了5个DEG（、、、和）进行qRT-PCR以验证转录组结果。预计对这些基因的进一步研究将有助于我们更好地了解扬子鳄胚胎后肢发育的过程。
