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

In this study, we identified 2 isoforms of the MBD2/3 gene inBombyx 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 inβ1 −β6 orα1 in the MBD showed thatβ2 −β3-turns in theβ-sheet of the MBD are necessary for the formation of the MBD2/3 –mCpG complex; furthermore, other secondary structures, namely,β4 −β6 and anα-helix, play a role in stabilizing theβ-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 regulatingB. mori embryonic development, similar to that of DNA methylation; however, MBD2/3-S withoutβ4 −β6 andα-helix does not alter embryonic development. These results suggest that MBD2/3-L recognizes and binds to mCpG through the intactβ-sheet structure in its MBD, thus ensuring silkworm embryonic development.

Source: Insect Science - April 10, 2023 Category: Biology Authors: Tong ‐Yu Fu, Shuang‐Shun Ji, Yu‐Lin Tian, Yi‐Guang Lin, Yu‐Mei Chen, Qi‐En Zhong, Si‐Chun Zheng, Guan‐Feng Xu Tags: ORIGINAL ARTICLE Source Type: research