Transcriptomic analysis reveals the regulation network of BmKrüppel homolog 1 in the oocyte development of Bombyx mori

Krüppel homolog 1 (Kr‐h1), a zinc finger transcription factor, is involved in the metamorphosis and adult reproduction of insects. However, the role of Kr‐h1 in reproduction of holometabolic insects remains to be elucidated. The regulation network of Kr‐h1‐associated genes in the reproduction in Bombyx mori was investigated in this study. The higher expression level of BmKr‐h1 in the ovaries was detected during the late pupal stage and adults. RNA interference (RNAi)‐mediated depletion of BmKr‐h1 in the female at day 6 of pupae resulted in abnormal oocytes at 48 h post‐double‐stranded RNA treatment, which showed less yolk protein deposition and partially transparent chorion. RNA‐seq and subsequent differentially expressed transcripts analysis showed that knockdown of BmKr‐h1 caused a decrease in the expression of 2882 genes and an increase in the expression of 2565 genes in the oocytes at day 8 of pupae. Totally, 27 genes coding for transcription factors were down‐regulated, while six genes coding for other transcription factors were up‐regulated. BmKr‐h1 bound to the Kr‐h1 binding site of the transcription factors AP‐1 (activating protein‐1) and FOXG1 to increase their messenger RNA transcripts in the BmN cells, respectively. Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses of that positively co‐expressed with AP‐1 and FOXG1 transcripts showed mainly enrichment in the metabolic‐related pathways, the nutrient absorption and the yolk protein absorption processes. These data suggested that BmKr‐h1 might directly regulate the metabolic‐related pathways, the nutrient absorption and the yolk protein absorption processes or probably through AP‐1 and /or FOXG1 to regulate oocyte development.