title: Drosophila mind bomb2 is required for maintaining muscle integrity and survival.
abstract: We report that the Drosophila mind bomb2 (mib2) gene is a novel regulator of muscle development. Unlike its paralogue, mib1, zygotic expression of mib2 is restricted to somatic and visceral muscle progenitors, and their respective differentiated musculatures. We demonstrate that in embryos that lack functional Mib2, muscle detachment is observed beginning in mid stage 15 and progresses rapidly, culminating in catastrophic degeneration and loss of most somatic muscles by stage 17. Notably, the degenerating muscles are positive for apoptosis markers, and inhibition of apoptosis in muscles prevents to a significant degree the muscle defects. Rescue experiments with Mib1 and Neuralized show further that these E3 ubiquitin ligases are not capable of ameliorating the muscle mutant phenotype of mib2. Our data suggest strongly that mib2 is involved in a novel Notch- and integrin-independent pathway that maintains the integrity of fully differentiated muscles and prevents their apoptotic degeneration.
authors.affiliation: Department of Medicine, Division of Cardiology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: Hanh T
authors.initials: HT
authors.lastname: Nguyen
authors.forename: Francesca
authors.initials: F
authors.lastname: Voza
authors.forename: Nader
authors.initials: N
authors.lastname: Ezzeddine
authors.forename: Manfred
authors.initials: M
authors.lastname: Frasch
mesh_terms: D000483:Alleles; D000818:Animals; D017209:Apoptosis; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002470:Cell Survival; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology* / Q000201:enzymology / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D016023:Integrins / Q000378:metabolism; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D024510:Muscle Development; D009132:Muscles / Q000166:cytology* / Q000196:embryology* / Q000201:enzymology / Q000378:metabolism; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D021381:Protein Transport; D051880:Receptors, Notch / Q000378:metabolism; D015398:Signal Transduction; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D014781:Viscera / Q000166:cytology / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D029721:Drosophila Proteins; D016023:Integrins; C524693:Mib2 protein, Drosophila; D050505:Mutant Proteins; D051880:Receptors, Notch; D044767:Ubiquitin-Protein Ligases