title: Quantitative profiling of Drosophila melanogaster Dscam1 isoforms reveals no changes in splicing after bacterial exposure.
abstract: The hypervariable Dscam1 (Down syndrome cell adhesion molecule 1) gene can produce thousands of different ectodomain isoforms via mutually exclusive alternative splicing. Dscam1 appears to be involved in the immune response of some insects and crustaceans. It has been proposed that the diverse isoforms may be involved in the recognition of, or the defence against, diverse parasite epitopes, although evidence to support this is sparse. A prediction that can be generated from this hypothesis is that the gene expression of specific exons and/or isoforms is influenced by exposure to an immune elicitor. To test this hypothesis, we for the first time, use a long read RNA sequencing method to directly investigate the Dscam1 splicing pattern after exposing adult Drosophila melanogaster and a S2 cell line to live Escherichia coli. After bacterial exposure both models showed increased expression of immune-related genes, indicating that the immune system had been activated. However there were no changes in total Dscam1 mRNA expression. RNA sequencing further showed that there were no significant changes in individual exon expression and no changes in isoform splicing patterns in response to bacterial exposure. Therefore our studies do not support a change of D. melanogaster Dscam1 isoform diversity in response to live E. coli. Nevertheless, in future this approach could be used to identify potentially immune-related Dscam1 splicing regulation in other host species or in response to other pathogens.
authors.affiliation: Institute for Evolution and Biodiversity, University of Münster, Münster, Germany.
authors.forename: Sophie A O
authors.initials: SA
authors.lastname: Armitage
authors.affiliation: Laboratory for Novel Sequencing Technology, Functional and Medical Genomics, Berlin Institute for Medical Systems Biology, Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.affiliation: Laboratory for Novel Sequencing Technology, Functional and Medical Genomics, Berlin Institute for Medical Systems Biology, Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany.
authors.forename: Xintian
authors.initials: X
authors.lastname: You
authors.affiliation: Institute for Evolution and Biodiversity, University of Münster, Münster, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Kurtz
authors.affiliation: Laboratory of Neuronal Wiring, Vesalius Research Center, VIB, Department of Oncology, University Leuven, Leuven, Belgium.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schmucker
authors.affiliation: Laboratory for Novel Sequencing Technology, Functional and Medical Genomics, Berlin Institute for Medical Systems Biology, Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D015815:Cell Adhesion Molecules; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster; D004926:Escherichia coli / Q000235:genetics; D019006:Neural Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D017423:Sequence Analysis, RNA
chemical_list: D015815:Cell Adhesion Molecules; D029721:Drosophila Proteins; C491736:Dscam1 protein, Drosophila; D019006:Neural Cell Adhesion Molecules; D020033:Protein Isoforms