Zinc finger protein,an important transcription factor,regulates gene expres-sion associated with various physiological and pathological processes.U-shaped,belong to the Friend of GATA(FOG)transcription factor,plays a crucial role in hematopoiesis by interacting with the GATA transcription factor as a co-factor.However,little is known about its functions in insects.In the present study,a U-shaped cDNA was identified and characterized from the silkworm Bombyx mori and its potential roles in innate immunity investigated.The predicted silkworm U-shaped amino acid sequence contained a classical nuclear localization signal(NLS)motif"GESSPKRRRR"at position 450-459,and argi-nine residues at position 456 and 478 are the critical sites of the NLS.U-shaped mRNA was detected in all tested tissues of the B.mori;however,the highest levels were found in the hemocytes.U-shaped mRNA expression levels were upregulated in the hemocyte after the Escherichia coli and Staphylococcus aureus challenge.Furthermore,U-shaped knockdown significantly reduced the melanization process and suppressed the expression of melanization-associated genes,including PPO1,PPO2,PPAE and BAEE.In addition,U-shaped interacts with Lozenge protein to regulate the innate immune response of the insect.Our results revealed that U-shaped binds directly to Lozenge protein to modulate the melanization process and innate immune responses in silkworm.

Lozenge蛋白(Lz蛋白)是昆虫的重要转录因子,在昆虫胚胎发育过程中发挥重要作用.为研究Lozenge在西方蜜蜂Apis mellifera中的作用,本研究克隆了Lozenge基因,并对其进行生物信息学分析,同时基于荧光定量PCR技术检测该基因在西方蜜蜂不同发育时期(卵期、幼虫期、蛹期和成年蜂)和 10 日龄哺育蜂各组织的表达谱.生物信息学分析结果显示,Lozenge基因的开放阅读框(ORF)为1554 bp,共编码 517 个氨基酸,预测分子量为54.63918 kDa,等电点为6.08;结构域预测分析发现Lozenge蛋白含有一个Runt结构域,多物种蛋白序列对比发现该蛋白同源性高.时期表达谱表明,该基因在第1 日卵和第 2 日卵的表达量远高于其他时期,在卵期表达量随时间依次递减,幼虫期表达量极低,蛹期表达量呈先增后减的趋势,而成年蜂中均有表达;组织表达谱显示,该基因在哺育蜂头部、上颚腺中的表达量较高,而在腹部的表达量低.这些结果表明,Lozenge基因可能在西方蜜蜂胚胎期细胞发育过程、哺育蜂蜂王浆合成和分泌过程中发挥重要作用,这些结果为该基因功能的深入研究提供了重要的理论参考.