title: Genes encoding novel secreted and transmembrane proteins are temporally and spatially regulated during Drosophila melanogaster embryogenesis.
abstract: BACKGROUND
  Morphogenetic events that shape the Drosophila melanogaster embryo are tightly controlled by a genetic program in which specific sets of genes are up-regulated. We used a suppressive subtractive hybridization procedure to identify a group of developmentally regulated genes during early stages of D. melanogaster embryogenesis. We studied the spatiotemporal activity of these genes in five different intervals covering 12 stages of embryogenesis.
  
  
  RESULTS
  Microarrays were constructed to confirm induction of expression and to determine the temporal profile of isolated subtracted cDNAs during embryo development. We identified a set of 118 genes whose expression levels increased significantly in at least one developmental interval compared with a reference interval. Of these genes, 53% had a phenotype and/or molecular function reported in the literature, whereas 47% were essentially uncharacterized. Clustering analysis revealed demarcated transcript groups with maximum gene activity at distinct developmental intervals. In situ hybridization assays were carried out on 23 uncharacterized genes, 15 of which proved to have spatiotemporally restricted expression patterns. Among these 15 uncharacterized genes, 13 were found to encode putative secreted and transmembrane proteins. For three of them we validated our protein sequence predictions by expressing their cDNAs in Drosophila S2R+ cells and analyzed the subcellular distribution of recombinant proteins. We then focused on the functional characterization of the gene CG6234. Inhibition of CG6234 by RNA interference resulted in morphological defects in embryos, suggesting the involvement of this gene in germ band retraction.
  
  
  CONCLUSIONS
  Our data have yielded a list of developmentally regulated D. melanogaster genes and their expression profiles during embryogenesis and provide new information on the spatiotemporal expression patterns of several uncharacterized genes. In particular, we recovered a substantial number of unknown genes encoding putative secreted and transmembrane proteins, suggesting new components of signaling pathways that might be incorporated within the existing regulatory networks controlling D. melanogaster embryogenesis. These genes are also good candidates for additional targeted functional analyses similar to those we conducted for CG6234.See related minireview by Vichas and Zallen: http://www.jbiol.com/content/8/8/76.
authors.affiliation: Laboratorio de Bioinformática y Expresión Génica, INTA-Universidad de Chile, Millennium Nucleus Center for Genomics of the Cell (CGC), Santiago, Chile. jano@inta.cl
authors.forename: Alejandro
authors.initials: A
authors.lastname: Zúñiga
authors.forename: Christian
authors.initials: C
authors.lastname: Hödar
authors.forename: Patricia
authors.initials: P
authors.lastname: Hanna
authors.forename: Freddy
authors.initials: F
authors.lastname: Ibáñez
authors.forename: Pablo
authors.initials: P
authors.lastname: Moreno
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Pulgar
authors.forename: Luis
authors.initials: L
authors.lastname: Pastenes
authors.forename: Mauricio
authors.initials: M
authors.lastname: González
authors.forename: Verónica
authors.initials: V
authors.lastname: Cambiazo
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics*; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation / Q000235:genetics
chemical_list: D029721:Drosophila Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger