Abstract: Objective　To characterize the epidermal growth factor receptor (EGFR) gene in Schistosoma japonicum (SjEGFR gene) and investigate the role of the EGFR gene in regulating the growth, reproductive system, maturation and fecundity of S. japonicum. Methods　Rapid amplification of cDNA ends (RACE) was performed to obtain the full length of the SjEGFR gene, and the SjEGFR gene expression was quantified in different developmental stages of S. japonicum using a quantitative real-time PCR (qPCR) assay. The tissue localization of the SjEGFR gene was detected in 22-day parasite using whole-mount in situ hybridization (WISH). Following RNA interference (RNAi)-induced knockdown of the SjEGFR gene, the worm length, pairing rate and worm burden of S. japonicum were measured, and the worm morphology was observed using optical microscopy and confocal microscopy. Results　The SjEGFR gene was identified with a conserved tyrosine-kinase active site, and the SjEGFR gene expression was detected at various developmental stages in male and female parasites. WISH showed that the transcript of the SjEGFR gene was localized on the tegument and in the digestive organs of S. japonicum. RNAi-induced SjEGFR knockdown resulted in marked suppression of the worm growth, smaller size of male testicles that contained more immature spermatocytes, and apparent impairment of ovary and vitelline gland development. In addition, no eggs were found in the uterus of SjEGFR knocked-down female parasites, indicating the interruption of egg production. Conclusions　Inhibition of SjEGFR expression may remarkably suppress the growth and maturation of S. japonicum, and interrupt the egg production

Key words: Schistosoma japonicum, Epidermal growth factor receptor, Reproduction, Maturation

摘要： 目的　鉴定日本血吸虫表皮生长因子受体基因（SjEGFR），并阐明其在日本血吸虫生长和生殖发育中的作用。方法　通过5'-RACE 和3'-RACE扩增、测序获取SjEGFR基因全长片段。采用荧光定量PCR（qPCR）技术检测该基因在日本血吸虫不同发育阶段（16、18、20、22、24、26 d）表达情况。使用整条虫体原位杂交法对感染24 d的日本血吸虫雌、雄虫SjEGFR基因转录本进行定位。通过体内持续RNA干扰（RNAi）技术特异性敲低SjEGFR基因，待虫体发育至30 d收集虫体。统计分析雌、雄虫回收数量以及虫体长度，通过明矾卡红染色观察虫体生长发育情况。结果　首次鉴定了SjEGFR基因，其结构具有一个保守的酪氨酸激酶位点。整条虫体原位杂交定位显示该基因转录本在虫体各处均有表达，在雌、雄虫肠道部位呈现出明显着色的高表达。体内RNAi显示，SjEGFR基因表达被特异性敲低后，雌、雄虫生长受阻。RNAi组雌虫子宫内无虫卵，肠道内无色素沉积、卵黄腺发育迟滞、卵巢发育受阻；雄虫呈现睾丸个数减少、体积变小，出现了更多未成熟的精母细胞。结论　特异性敲低SjEGFR基因表达可影响日本血吸虫生长和生殖发育，阻滞虫卵产生。

关键词: 日本血吸虫, 表皮生长因子受体, 生殖, 成熟