title: Calcineurin function is required for myofilament formation and troponin I isoform transition in Drosophila indirect flight muscle.
abstract: Mutations in the Drosophila calcineurin B2 gene cause the collapse of indirect flight muscles during mid stages of pupal development. Examination of cell fate-specific markers indicates that unlike mutations in genes such as vestigial, calcineurin B2 does not cause a shift in cell fate from indirect flight muscle to direct flight muscle. Genetic and molecular analyses indicate a severe reduction of myosin heavy chain gene expression in calcineurin B2 mutants, which accounts at least in part for the muscle collapse. Myofibrils in calcineurin B2 mutants display a variety of phenotypes, ranging from normal to a lack of sarcomeric structure. Calcineurin B2 also plays a role in the transition to an adult-specific isoform of troponin I during the late pupal stages, although the incompleteness of this transition in calcineurin B2 mutants does not contribute to the phenotype of muscle collapse. Together, these findings suggest a molecular basis for the indirect flight muscle hypercontractility phenotype observed in flies mutant for Drosophila calcineurin B2.
authors.affiliation: Department of Biochemistry and Molecular Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. kwgajews@mdanderson.org
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Gajewski
authors.forename: Jianbo
authors.initials: J
authors.lastname: Wang
authors.forename: Robert A
authors.initials: RA
authors.lastname: Schulz
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism*; D000483:Alleles; D017398:Alternative Splicing; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D019703:Calcineurin / Q000235:genetics / Q000502:physiology*; D004330:Drosophila / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D018260:Gelsolin / Q000235:genetics / Q000378:metabolism; D009119:Muscle Contraction / Q000502:physiology; D024510:Muscle Development; D009132:Muscles / Q000378:metabolism / Q000648:ultrastructure; D009154:Mutation; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D019210:Troponin I / Q000235:genetics / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D029721:Drosophila Proteins; D018260:Gelsolin; D020033:Protein Isoforms; D019210:Troponin I; C098178:fliI protein, Drosophila; D019703:Calcineurin; D018995:Myosin Heavy Chains