Details

Autor(en) / Beteiligte

• Fu, Tong‐Yu
• Ji, Shuang‐Shun
• Tian, Yu‐Lin
• Lin, Yi‐Guang
• Chen, Yu‐Mei
• Zhong, Qi‐En
• Zheng, Si‐Chun
• Xu, Guan‐Feng

Titel

Methyl‐CpG binding domain (MBD)2/3 specifically recognizes and binds to the genomic mCpG site with a β‐sheet in the MBD to affect embryonic development in Bombyx mori

Ist Teil von

• Insect science, 2023-12, Vol.30 (6), p.1607-1621

Ort / Verlag

Australia: Wiley Subscription Services, Inc

Erscheinungsjahr

2023

Quelle

Wiley Blackwell Single Titles

Beschreibungen/Notizen

• Methyl‐CpG (mCpG) binding domain (MBD) proteins especially bind with methylated DNA, and are involved in many important biological processes; however, the binding mechanism between insect MBD2/3 and mCpG remains unclear. In this study, we identified 2 isoforms of the MBD2/3 gene in Bombyx mori, MBD2/3‐S and MBD2/3‐L. Binding analysis of MBD2/3‐L, MBD2/3‐S, and 7 mutant MBD2/3‐L proteins deficient in β1−β6 or α1 in the MBD showed that β2−β3‐turns in the β‐sheet of the MBD are necessary for the formation of the MBD2/3–mCpG complex; furthermore, other secondary structures, namely, β4−β6 and an α‐helix, play a role in stabilizing the β‐sheet structure to ensure that the MBD is able to bind mCpG. In addition, sequence alignment and binding analyses of different insect MBD2/3s indicated that insect MBD2/3s have an intact and conserved MBD that binds to the mCpG of target genes. Furthermore, MBD2/3 RNA interference results showed that MBD2/3‐L plays a role in regulating B. mori embryonic development, similar to that of DNA methylation; however, MBD2/3‐S without β4−β6 and α‐helix does not alter embryonic development. These results suggest that MBD2/3‐L recognizes and binds to mCpG through the intact β‐sheet structure in its MBD, thus ensuring silkworm embryonic development. The β‐sheet (β2–β3) in the methyl‐CpG (mCpG) binding domain (MBD) of MBD2/3 embeds in the major groove at the mCpG site, and other secondary structures (β4−β6 and α1) help stabilize the β‐sheet structure, thus enabling MBD2/3 to specifically bind with the methyl‐CpG of genes, thereby regulating gene expression and ensuring the B. mori embryonic development.