【目的】 本文旨在挖掘野生型家蚕Bombyx mori和Ras1CA过表达转基因家蚕后部丝腺中的转录本差异，分析和验证细胞周期通路中的差异表达基因，从而探讨Ras1CA过表达转基因家蚕提高蚕丝产量的分子机制。【方法】 利用转录组学比较野生型和Ras1CA过表达转基因家蚕后部丝腺中的基因转录本差异，经实时荧光定量PCR（qRT-PCR）验证。【结果】 野生型家蚕和Ras1CA过表达转基因家蚕后部丝腺组织中有2 636个差异表达基因，其中细胞周期信号通路中有42个差异表达基因，包括细胞周期依赖性激酶（CDK）、细胞周期素（Cyclin）以及转录因子等。通过qRT-PCR检测cdk1、cyclinD1、cyclinD2、cdc7、cdh1、dp-1,2等6个基因在野生型和Ras1CA过表达转基因家蚕后部丝腺组织中的相对表达量，发现转基因家蚕中的表达量均显著高于野生型（P<0.05），其中cyclinD2的表达差异极显著（P<0.01）。qRT-PCR结果与转录本差异一致，表明Ras1CA过表达后，能够促进细胞周期通路基因的表达。【结论】 野生型家蚕和Ras1CA过表达转基因家蚕后部丝腺中有大量差异表达基因，且Ras1CA能够在转录水平上调控细胞周期通路，影响后部丝腺组织的细胞分裂和器官生长，从而促进蚕丝蛋白的合成。

[Objectives]  To further understand the molecular mechanisms underlying the overexpression of the Ras1^CA oncogene in the posterior silk gland (PSG) of Bombyx mori and how this improves silk yield at the transcriptional level. Transcriptomic data from differentially expressed genes (DEGs) in the cell cycle pathway of Ras1^CA-overexpressed and wild type PSG were analyzed and verified by quantitative real-time PCR (qRT-PCR). [Methods]  Deep RNA sequencing of silkworm PSG was carried out and KEGG pathway enrichment analysis was conducted on the DEGs. The DEGs in the cell cycle pathway was selected to be verified by qRT-PCR. [Results]  RNA-Seq revealed 2 636 DEGs in Ras1^CA-overexpressed PSG compared to wild type PSG. There were 42 DEGs distributed in the “cell cycle” pathway, including cyclin dependent kinases (CDKs), cyclins and transcription factors. Consistent with the transcriptomic data, qRT-PCR verification of the selected genes; cdk1, cyclinD1, cyclinD2, cdc7, cdh1, dp-1,2, indicated that all of these were significantly upregulated by Ras1^CA. [Conclusion]  Transcriptomic analysis revealed that there are a number of DEGs in Ras1^CA-overexpressed and wild type PSG. Ras1^CA-overexpression upregulates some DEGs in the cell cycle pathway that benefit silk gland growth and fibroin synthesis. These results advance our knowledge of the molecular mechanism underlying how Ras1^CA-overexpression in the PSG improves fibroin production and silk production.