DNA methylation suppresses chitin degradation and promotes the wing development by inhibiting Bmara-mediated chitinase expression in the silkworm, Bombyx mori

Abstract

Background: DNA methylation, as an essential epigenetic modification found in mammals and plants, has been implicated to play an important role in insect reproduction. However, the functional role and the regulatory mechanism of DNA methylation during insect organ or tissue development are far from being clear. Results: Here, we found that DNA methylation inhibitor (5-aza-dC) treatment in newly molted pupae decreased the chitin content of pupal wing discs and adult wings and resulted in wing deformity of Bombyx mori. Transcriptome analysis revealed that the up-regulation of chitinase 10 (BmCHT10) gene might be related to the decrease of chitin content induced by 5-aza-dC treatment. Further, the luciferase activity assays demonstrated that DNA methylation suppressed the promoter activity of BmCHT10 by down-regulating the transcription factor, homeobox protein araucan (Bmara). Electrophoretic mobility shift assay, DNA pull-down and chromatin immunoprecipitation demonstrated that Bmara directly bound to the BmCHT10 promoter. Therefore, DNA methylation is involved in keeping the structural integrity of the silkworm wings from unwanted chitin degradation, as a consequence, it promotes the wing development of B. mori. Conclusions: This study reveals that DNA methylation plays an important role in the wing development of B. mori. Our results support that the indirect transcriptional repression of a chitin degradation-related gene BmCHT10 by DNA methylation is necessary to keep the proper wing development in B. mori.

Effect of Tachinid Parasitoid Exorista japonica on the Larval Development and Pupation of the Host Silkworm Bombyx mori

“…The method for chitin measurement was performed as previously described and modified (Xu et al, 2020). Briefly, epidermis samples from silkworm prepupae were collected and homogenized in 400 µl 3% sodium dodecyl sulfate (SDS), incubated at 100 • C for 15 min and centrifuged, then washed the precipitate with double distilled H 2 O (ddH 2 O) and resuspended in 400 µl 14 mol/l KOH, incubated at 130 • C for 1 h. Then, the sample was mixed with 800 µl ice-cold 75% ethanol, incubated on ice for 15 min, and then mixed with 300 µl celite suspension.…”

Novel Therapeutic Mechanism of Adipose-Derived Mesenchymal Stem Cells in Osteoarthritis via Upregulation of BTG2

“…DNA Pulldown Assay. As previously described [25], DNA pulldown assay was conducted to prove the affinity of KLF4 to BTG2 promoter. Cell lysates and BTG2 promoter-specific biotinylated probes were incubated for 2 h at room temperature with streptavidin-agarose beads to form DNA-protein-beads complexes.…”

Comparative transcriptome analysis reveals regional specialization of gene expression in larval silkworm (Bombyx mori) midgut

“…Four homeobox genes were confirmed to be expressed in different midgut regions. Bmara was identified to regulate chitinase expression in pupal wing discs (Xu et al ., 2020). In the midgut, Bmara was highly expressed in AMG (Fig.…”