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  

作　　者：Tong-Yu Fu Shuang-Shun Ji Yu-Lin Tian Yi-Guang Lin Yu-Mei Chen Qi-En Zhong Si-Chun Zheng Guan-Feng Xu 

机构地区：[1]Guangdong Provincial Key Laboratory of Insect Developmental Biology and Applied Technology,Guangzhou Key Laboratory of Insect Development Regulation and Application Research,Institute of Insect Science and Technology,School of Life Sciences,South China Normal University,Guangzhou,China

出　　处：《Insect Science》2023年第6期1607-1621,共15页昆虫科学（英文版）

基　　金：funded by the National Natural Sci-ence Foundation of China,grant numbers 32100374 and 31872286.

摘　　要：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 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 regulating B.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.

关 键 词：embryonic development insects MBD2/3 methyl-CpG binding domain(MBD) Β-SHEET 

分 类 号：Q96[生物学—昆虫学]