Table of Contents Author Guidelines Submit a Manuscript
Journal of Biomedicine and Biotechnology
Volume 2009, Article ID 315423, 9 pages
http://dx.doi.org/10.1155/2009/315423
Research Article

Gene Expression Divergence and Evolutionary Analysis of the Drosomycin Gene Family in Drosophila melanogaster

1The Key Laboratory of Gene Engineering of Ministry of Education, Sun Yat-sen University, Guangzhou 510275, China
2Department of Sericulture Science, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
3Biopharmaceutical Research and Development Center, Jinan University, Guangzhou 510632, China
4Department of Entomology, College of Natural Resource and Environment, South China Agricultural University, Guangzhou 510642, China
5Key Sericultural Laboratory of Agriculture Ministry, College of Sericulture and Biotechnology, Southwest University, Chongqing 400716, China

Received 17 March 2009; Revised 6 June 2009; Accepted 7 August 2009

Academic Editor: Mouldy Sioud

Copyright © 2009 Xiao-Juan Deng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Drosomycin (Drs) encoding an inducible 44-residue antifungal peptide is clustered with six additional genes, Dro1, Dro2, Dro3, Dro4, Dro5, and Dro6, forming a multigene family on the 3L chromosome arm in Drosophila melanogaster. To get further insight into the regulation of each member of the drosomycin gene family, here we investigated gene expression patterns of this family by either microbe-free injury or microbial challenges using real time RT-PCR. The results indicated that among the seven drosomycin genes, Drs, Dro2, Dro3, Dro4, and Dro5 showed constitutive expressions. Three out of five, Dro2, Dro3, and Dro5, were able to be upregulated by simple injury. Interestingly, Drs is an only gene strongly upregulated when Drosophila was infected with microbes. In contrast to these five genes, Dro1 and Dro6 were not transcribed at all in either noninfected or infected flies. Furthermore, by rapid amplification of cDNA ends, two transcription start sites were identified in Drs and Dro2, and one in Dro3, Dro4, and Dro5. In addition, NF- B binding sites were found in promoter regions of Drs, Dro2, Dro3, and Dro5, indicating the importance of NF- B binding sites for the inducibility of drosomycin genes. Based on the analyses of flanking sequences of each gene in D. melanogaster and phylogenetic relationship of drosomycins in D. melanogaster species-group, we concluded that gene duplications were involved in the formation of the drosomycin gene family. The possible evolutionary fates of drosomycin genes were discussed according to the combining analysis of gene expression pattern, gene structure, and functional divergence of these genes.