[show abstract][hide abstract] ABSTRACT: Transcription factors are present in all living organisms, and play vital roles in a wide range of biological processes. Studies of transcription factors will help reveal the complex regulation mechanism of organisms. So far, hundreds of domains have been identified that show transcription factor activity. Here, 281 reported transcription factor domains were used as seeds to search the transcription factors in genomes of Bombyx mori L. (Lepidoptera: Bombycidae) and four other model insects. Overall, 666 transcription factors including 36 basal factors and 630 other factors were identified in B. mori genome, which accounted for 4.56% of its genome. The silkworm transcription factors' expression profiles were investigated in relation to multiple tissues, developmental stages, sexual dimorphism, and responses to oral infection by pathogens and direct bacterial injection. These all provided rich clues for revealing the transcriptional regulation mechanism of silkworm organ differentiation, growth and development, sexual dimorphism, and response to pathogen infection.
Journal of Insect Science 01/2012; 12:40. · 0.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Host-pathogen interactions are complex relationships, and a central challenge is to reveal the interactions between pathogens and their hosts. Bacillus bombysepticus (Bb) which can produces spores and parasporal crystals was firstly separated from the corpses of the infected silkworms (Bombyx mori). Bb naturally infects the silkworm can cause an acute fuliginosa septicaemia and kill the silkworm larvae generally within one day in the hot and humid season. Bb pathogen of the silkworm can be used for investigating the host responses after the infection. Gene expression profiling during four time-points of silkworm whole larvae after Bb infection was performed to gain insight into the mechanism of Bb-associated host whole body effect. Genome-wide survey of the host genes demonstrated many genes and pathways modulated after the infection. GO analysis of the induced genes indicated that their functions could be divided into 14 categories. KEGG pathway analysis identified that six types of basal metabolic pathway were regulated, including genetic information processing and transcription, carbohydrate metabolism, amino acid and nitrogen metabolism, nucleotide metabolism, metabolism of cofactors and vitamins, and xenobiotic biodegradation and metabolism. Similar to Bacillus thuringiensis (Bt), Bb can also induce a silkworm poisoning-related response. In this process, genes encoding midgut peritrophic membrane proteins, aminopeptidase N receptors and sodium/calcium exchange protein showed modulation. For the first time, we found that Bb induced a lot of genes involved in juvenile hormone synthesis and metabolism pathway upregulated. Bb also triggered the host immune responses, including cellular immune response and serine protease cascade melanization response. Real time PCR analysis showed that Bb can induce the silkworm systemic immune response, mainly by the Toll pathway. Anti-microorganism peptides (AMPs), including of Attacin, Lebocin, Enbocin, Gloverin and Moricin families, were upregulated at 24 hours post the infection.
PLoS ONE 01/2009; 4(12):e8098. · 3.73 Impact Factor