Hox genes of proboscipedia (pb) and Sex combs reduced (Scr) and their cofactors are required for determination of insect mouthpart identity and play important roles in insect organ morphogenesis. However, in the lepidopteran insects, including many agricultural and forest pests, the roles of these genes in determination of mouthpart morphogenesis are unclear. Here we report that both BmPB (Gene ID: 101740380) and BmSCR (Gene ID: 692761) are essential for labial palpus specification in a lepidopteran model insect, the silkworm, Bombyx mori. During embryonic morphogenesis, CRISPR/Cas9-mediated mutagenesis of BmPB induced transformation of labial palpus into thoracic leg and BmSCR mutation transformed labial palpus into maxilla. Mutagenesis of Hox-related cofactor extradenticle (BmEXD; Gene ID: 692478) and its nuclear localization factor homothorax (BmHTH; Gene ID: 576938425) also induced distortion of embryonic labial palpus. Furthermore, mutagenesis of each of the four genes induced severe degeneration of spigot morphogenesis, an important part of spinneret structure. Quantitative real-time PCR analysis further revealed that the transcriptional interaction among these genes. Our data thus provide novel evidence for Hox gene regulation of insect embryonic patterning.

的Hox基因proboscipedia（PB）和性别梳减少（血肌酐）及其辅助因子都需要确定昆虫口器的身份，并在昆虫器官形态发生中起重要作用。然而，在鳞翅目昆虫，包括许多农业和森林害虫中，这些基因在确定口部形态发生中的作用尚不清楚。在这里，我们报告BmPB（基因ID：101740380）和BmSCR（基因ID：692761）对鳞翅目昆虫，家蚕Bombyx mori中的唇部palpus规格都是必不可少的。在胚胎形态发生过程中，CRISPR / Cas9介导的BmPB诱变唇下颚须的诱导转化成胸腿和BmSCR突变转化唇下颚须到颌骨。Hox相关辅因子齿外（BmEXD；基因ID：692478）及其核定位因子同型胸腔（BmHTH；基因ID：576938425）的诱变也诱导了胚胎唇唇的变形。此外，诱变的四个基因中的每一个都引起突节形态的严重退化，这是喷丝头结构的重要组成部分。实时定量PCR分析进一步揭示了这些基因之间的转录相互作用。因此，我们的数据为昆虫昆虫图案的Hox基因调控提供了新的证据。