Chi Yali, Feng Tao, Du Zixin, Huang Ping, Yu Wenjun, Liu Haihua, Wang Wanshan, Yang Xinping, Huang Liping
Department of Obstetrics & Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
Department of Hearing and Speech-Language Science, Guangzhou Xinhua University, Guangzhou, 510520, China.
BMC Biol. 2025 Jul 1;23(1):167. doi: 10.1186/s12915-025-02224-9.
Copy number variations (CNVs) occurring on chromosome 16p11.2 are associated with various neurodevelopmental disorders, including autism spectrum disorder (ASD), schizophrenia, and intellectual disability. Among the genes situated within the critical CNV region, DOC2A is noteworthy. We generated frameshift mutations in doc2a (double C2-like domain-containing protein a) and its paralog doc2b (double C2-like domain-containing protein b) in zebrafish via CRISPR-Cas9 respectively and obtained double-mutant doc2adoc2b by mating the single-mutant doc2adoc2b and doc2adoc2b zebrafish.
doc2adoc2b mutants displayed aberrant morphology including tail bending and deformity, and morphologically normal individuals displayed aberrant behaviors, including reduced locomotion activity, impaired social interaction, and irregular movements. Whole-brain transcriptome sequencing of both wild-type and doc2adoc2b mutants revealed differentially expressed genes (DEGs) enriched with ASD candidate genes and synaptic signaling pathways, notably down-regulated gene npas4b (Neuronal PAS domain protein 4b). We found the downstream targets of the transcription factor Npas4b in the DEGs were mostly enriched in the synaptic signaling pathways. The npas4b knockout and knockdown zebrafish showed reduced locomotion activity and impaired social interaction similar to the behaviors observed in doc2adoc2b mutants.
This study suggests that DOC2A in the critical region of 16p11.2 may contribute to the pathogenesis of autism by interacting with other genes, such as DOC2B, and that the downregulation of NPAS4 may play an important role in autism.
16p11.2染色体上发生的拷贝数变异（CNV）与多种神经发育障碍相关，包括自闭症谱系障碍（ASD）、精神分裂症和智力残疾。在关键CNV区域内的基因中，DOC2A值得关注。我们分别通过CRISPR-Cas9在斑马鱼中产生了doc2a（含双C2样结构域蛋白a）及其旁系同源基因doc2b（含双C2样结构域蛋白b）的移码突变，并通过将单突变doc2a+/−doc2b−/−和doc2a−/−doc2b+/−斑马鱼交配获得了双突变doc2a−/−doc2b−/−。
doc2a−/−doc2b−/−突变体表现出异常形态，包括尾巴弯曲和畸形，形态正常的个体表现出异常行为，包括运动活性降低、社交互动受损和不规则运动。野生型和doc2a−/−doc2b−/−突变体的全脑转录组测序揭示了差异表达基因（DEG），这些基因富含ASD候选基因和突触信号通路，特别是下调基因npas4b（神经元PAS结构域蛋白4b）。我们发现DEG中转录因子Npas4b的下游靶点大多富集在突触信号通路中。npas4b基因敲除和敲低的斑马鱼表现出运动活性降低和社交互动受损，类似于在doc2a−/−doc2b−/−突变体中观察到的行为。
本研究表明，16p11.2关键区域的DOC2A可能通过与其他基因（如DOC2B）相互作用而导致自闭症发病机制，并且NPAS4的下调可能在自闭症中起重要作用。
