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Bioinformatic Approaches to the Study of Insect Neuropeptides with Particular Emphasis on the Allatostatins

出版	Library and Archives Canada = Bibliothèque et Archives Canada, 2006
ISBN	04941596509780494159651
URL	http://books.google.com.hk/books?id=e9dVNwAACAAJ&hl=&source=gbs_api

註釋Neuropeptides called allatostatins (ASTs) were first identified in the cockroach Diploptera punctata on the basis of their ability to inhibit the biosynthesis of the juvenile hormone. We predicted putative antigenic sequential epitopes on the surface of the Drosophila allatostatin receptor DAR-2 by analyzing the primary amino acid sequence. A peptide derived from one epitope was then used to immunize rabbits, producing antisera which blocked radiolabelled AST binding to cell membranes. Identifying regulatory elements within non-coding genomic regions has been called one of the most important goals of the post-genomic era. Comparing sequence information across species can identify DNA regions whose sequence conservation reflects conserved function. The YXFGLa-AST preprohormone gene Ast in D. melanogaster codes for four AST peptides. Genome assemblies for D. simulans, D. ananassae, D. yakuba, D. pseudoobscura, D. mojavensis and D. grimshawi were screened against Ast in order to identify orthologous genes. The ASTs are nearly identical across species with the exception of AST-1, in which the leading residue may be either methionine or valine. By applying phylogenetic footprinting techniques to the Ast orthologues, we identified potential transcription factor binding site motifs, representing four families of transcription factors that might be involved in regulating Ast expression. The distribution of putative DAR-2 receptors in the central nervous system of larval Drosophila was characterized with the antisera. Immunoreactivity in the brain appears to be associated with glial septa surrounding neuropil compartments, whereas immunoreactive cell bodies in the ventral ganglion appear to occupy the cortex surrounding the central neuropil. Five cell bodies in the region of the ring gland corresponding to the corpora cardiaca are intensely immunolabelled by both DAR-2 and AST antisera.'Mining' the data generated by microarray experiments conducted to study the metamorphic transition of the Drosophila midgut reveals small changes in the expression of genes coding for known neuropeptides and neuropeptide receptors. Diuretic hormone, YXFGLa-ASTs, myoinhibiting peptide, ecdysis-triggering hormone, drosokinin, and the burs subunit of bursicon, as well as the receptors DAR-2, NPFR1, ALCR-2, Lkr and DH-R, all show evidence of regulation during midgut metamorphosis.