Reference gene selection for quantitative real-time polymerase chain reaction analysis in Bombyx mori nucleopolyhedrovirus-infected silkworms
Keywords:Bombyx mori, reference genes, BmNPV, qPCR, immune genes
Bombyx mori nucleopolyhedrovirus (BmNPV) is the most serious viral disease in silkworms. To investigate the mechanisms of the immune responses of B. mori to a BmNPV infection, a suitable reference gene (RG) is necessary for normalizing data when studying the expression of genes in BmNPV-infected silkworms or cells. Thus, quantitative real-time PCR polymerase chain reaction was used to compare the stability of expression of nine potential RGs, including the actin A3, translation initiation factor 3 (TIF-3), TIF-A4, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), 18S RNA, 28S RNA, TATA-binding protein (TBP), ribosomal protein L3 (Rpl3), and α-tubulin genes, in silkworms infected with BmNPV. The results were analyzed by BestKeeper, geNorm, and NormFinder software. Overall, α-tubulin exhibited the most stable gene expression in BmNPV-infected silkworms, and this was verified by western blotting of the α-tubulin protein. Moreover, we detected the expression of some genes involved in the immune signaling pathways of silkworms after BmNPV infection using α-tubulin as an internal RG.