Identification and Analysis of the SET-Domain Family in Silkworm, Bombyx mori.

Hailong Zhao,Hongjuan Cui,Chunqin Zheng

doi:10.1155/2015/161287

Abstract

As an important economic insect, Bombyx mori is also a useful model organism for lepidopteran insect. SET-domain-containing proteins belong to a group of enzymes named after a common domain that utilizes the cofactor S-adenosyl-L-methionine (SAM) to achieve methylation of its substrates. Many SET-domain-containing proteins have been shown to display catalytic activity towards particular lysine residues on histones, but emerging evidence also indicates that various nonhistone proteins are specifically targeted by this clade of enzymes. To explore their diverse functions of SET-domain superfamily in insect, we identified, cloned, and analyzed the SET-domains proteins in silkworm, Bombyx mori. Firstly, 24 genes containing SET domain from silkworm genome were characterized and 17 of them belonged to six subfamilies of SUV39, SET1, SET2, SUV4-20, EZ, and SMYD. Secondly, SET domains of silkworm SET-domain family were intraspecifically and interspecifically conserved, especially for the catalytic core “NHSC” motif, substrate binding site, and catalytic site in the SET domain. Lastly, further analyses indicated that silkworm SET-domain gene BmSu(var)3-9 owned different characterization and expression profiles compared to other invertebrates. Overall, our results provide a new insight into the functional and evolutionary features of SET-domain family.

Highlights

SET-domain superfamily includes all but one of the methyltransferases that methylate specific site of histone lysine (K) residues involved in epigenetic regulation
Through transferring a methyl group from S-adenosyl-L-methionine (AdoMet) to the amino group of a lysine residue on different sites of histone proteins, SET-domain methyltransferases function in making different histone methylation marks
Histone methylation is very important for the chromatin modification and regulation of gene expression [1–4], which plays a crucial role in the animal development and a number of other biological processes, such as heterochromatin establishment, transcription regulation, parental imprinting, and cell fate destination

Summary

Introduction

SET-domain superfamily includes all but one of the methyltransferases that methylate specific site of histone lysine (K) residues involved in epigenetic regulation. This family is characterized by the highly conserved SET (Su(var)[3,4,5,6,7,8,9], E(z), Trithorax) domain that consists of approximately 130 amino acids and is responsible for the catalytic activity of these methyltransferases. Through transferring a methyl group from S-adenosyl-L-methionine (AdoMet) to the amino group of a lysine residue on different sites of histone proteins, SET-domain methyltransferases function in making different histone methylation marks. Members in each subfamily have very high similarity in the SET-domain amino acid sequence and in the flank motifs of SET domain

Methods

Results

Conclusion