Insect chitinases are hydrolytic enzymes that are required for the degradation of glycosidic bonds of chitin. compared to that of the control. Starvation also improved the manifestation of in the third-instar larvae and was suppressed again by re-feeding the bugs. These results suggest that plays an important part in the molting process of larvae and may be controlled by 20E. and offers 17 genes encoding chitinase, and [7] MK-0752 and [11], it is suggested that a part of the chitinases are essential for cuticle turnover, regulating abdominal contraction and wing growth. In addition, chitinases may be involved in additional physiological processes, such as immune defense [12] and disease control [13]. Chitinase activity in insects is at least in part under hormonal regulation, its activity being regulated by hormones, such as juvenile hormone (JH) and 20-hydroxyecdysone (20E) [14,15]. The influence of the hormones on the expression of chitinase genes has been evaluated in some lepidopteran insects [16,17]. 20E has been shown to stimulate the expression of these chitinase genes, but some of them could be suppressed by the simultaneous application of JH [18]. During insect larval development, a restricted supply of nutrients is critical for metamorphosis. In lepidopteran insects, starvation induces supernumerary molts associated with a high level of hemolymph JH titers [19]. However, in expression level can be decreased by feeding in (expression patterns after the treatment of 20E and starvation were also investigated. This study may provide some insights for further investigation about the chitin-degrading mechanism in the oriental fruit fly and other insects. 2.?Results 2.1. Sequence Analysis of cDNA The full-length cDNA sequence of (GenBank accession number: “type”:”entrez-nucleotide”,”attrs”:”text”:”JN100105″,”term_id”:”344227161″,”term_text”:”JN100105″JN100105) is usually MK-0752 1871 bp with an open reading frame (ORF) of 1449 bp, which encodes a protein of 483 amino acids with a predicted molecular mass of approximately 54.3 kDa and an isoelectric point of 5.97. The cDNA includes a 5-untranslated region (UTR) located 126 bp upstream of the start codon (ATG) and a 3-UTR of 296 bp that ends in a poly-A tail. The polyadenylation signal (AATAAA) was detected 55 bp upstream from the poly-A tail. The deduced protein BdCht2 seems to be a secretion protein, as a 28-amino acid signal peptide MK-0752 with a cleavage site (Ala 28) in the amino terminal region is present. The has three potential cDNA in was predicted to contain two domains, including a signal peptide and a single catalytic domain name. The glycosylhydrolase_18 conserved domain name (FDGLDLDWE) was found in BdCht2. However, no chitin binding domain name (CBD) was found at the and were 66%, 53%, 36% and 34%, respectively. According to the phylogenetic tree, chitinases were clearly classified into eight individual groups (ICVIII) and BdCht2 belonged to Group VII chitinase, which had only one representative chitinase gene in a variety of insect species (Physique 2). Physique 2 Phylogenetic analysis of chitinase and chitinase-like proteins from three insect species based on catalytic domain name sequences. A phylogenetic tree was constructed with MEGA (Molecular Evolutionary Genetics Analysis) 5.04 using the neighbor-joining method. … 2.2. Genomic DNA Structure and 5 Flanking Region of cDNA sequence, and the genomic sequence (“type”:”entrez-nucleotide”,”attrs”:”text”:”KF289944″,”term_id”:”549540747″,”term_text”:”KF289944″KF289944) was KRT4 in accordance with its cDNA sequence. The genomic sequence consists of 1709 bp and is comprised of four exons interrupted by three introns. In addition, the consensus GT and AG sequences at the 5 donor and 3 acceptor sites are conserved among the MK-0752 three introns (Physique 3). To identify the regulatory sequences involved in expression, we isolated a 977 bp DNA fragment upstream of the transcription start site ATG. Transcription factor binding sites were predicted using the TFSEARCH (Transcription Factor.