Skip to main content
NCBI home page
The Journal of Cell Biology logoLink to The Journal of Cell Biology
. 1991 Sep 1;114(5):941–951. doi: 10.1083/jcb.114.5.941

Muscle abnormalities in Drosophila melanogaster heldup mutants are caused by missing or aberrant troponin-I isoforms

PMCID: PMC2289106  PMID: 1908472

Abstract

We have investigated the molecular bases of muscle abnormalities in four Drosophila melanogaster heldup mutants. We find that the heldup gene encodes troponin-I, one of the principal regulatory proteins associated with skeletal muscle thin filaments. heldup3, heldup4, and heldup5 mutants, all of which have grossly abnormal flight muscle myofibrils, lack mRNAs encoding one or more troponin-I isoforms. In contrast, heldup2, an especially interesting mutant wherein flight muscles are atrophic, synthesizes the complete mRNA complement. By sequencing mutant troponin-I cDNAs we demonstrate that the molecular basis for muscle degeneration in heldup2 is conversion of an invariant alanine residue to valine. We finally show that degeneration of heldup2 thin filament/Z-disc networks can be prevented by eliminating thick filaments from flight muscles using a null allele of the sarcomeric myosin heavy chain gene. This latter observation suggests that actomyosin interactions exacerbate the structural or functional defect resulting from the troponin-I mutation.

Full Text

The Full Text of this article is available as a PDF (2.1 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Barbas J. A., Galceran J., Krah-Jentgens I., de la Pompa J. L., Canal I., Pongs O., Ferrús A. Troponin I is encoded in the haplolethal region of the Shaker gene complex of Drosophila. Genes Dev. 1991 Jan;5(1):132–140. doi: 10.1101/gad.5.1.132. [DOI] [PubMed] [Google Scholar]
  2. Beall C. J., Sepanski M. A., Fyrberg E. A. Genetic dissection of Drosophila myofibril formation: effects of actin and myosin heavy chain null alleles. Genes Dev. 1989 Feb;3(2):131–140. doi: 10.1101/gad.3.2.131. [DOI] [PubMed] [Google Scholar]
  3. Bonder E. M., Mooseker M. S. Direct electron microscopic visualization of barbed end capping and filament cutting by intestinal microvillar 95-kdalton protein (villin): a new actin assembly assay using the Limulus acrosomal process. J Cell Biol. 1983 Apr;96(4):1097–1107. doi: 10.1083/jcb.96.4.1097. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Chong P. C., Hodges R. S. Photochemical cross-linking between rabbit skeletal troponin subunits. Troponin I-troponin T interactions. J Biol Chem. 1982 Oct 10;257(19):11667–11672. [PubMed] [Google Scholar]
  5. Chun M., Falkenthal S. Ifm(2)2 is a myosin heavy chain allele that disrupts myofibrillar assembly only in the indirect flight muscle of Drosophila melanogaster. J Cell Biol. 1988 Dec;107(6 Pt 2):2613–2621. doi: 10.1083/jcb.107.6.2613. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Deak I. I., Bellamy P. R., Bienz M., Dubuis Y., Fenner E., Gollin M., Rähmi A., Ramp T., Reinhardt C. A., Cotton B. Mutations affecting the indirect flight muscles of Drosophila melanogaster. J Embryol Exp Morphol. 1982 Jun;69:61–81. [PubMed] [Google Scholar]
  7. Deak I. I. Mutations of Drosophila melanogaster that affect muscles. J Embryol Exp Morphol. 1977 Aug;40:35–63. [PubMed] [Google Scholar]
  8. Epstein H. F., Fischman D. A. Molecular analysis of protein assembly in muscle development. Science. 1991 Mar 1;251(4997):1039–1044. doi: 10.1126/science.1998120. [DOI] [PubMed] [Google Scholar]
  9. Falkenthal S., Parker V. P., Mattox W. W., Davidson N. Drosophila melanogaster has only one myosin alkali light-chain gene which encodes a protein with considerable amino acid sequence homology to chicken myosin alkali light chains. Mol Cell Biol. 1984 May;4(5):956–965. doi: 10.1128/mcb.4.5.956. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Fyrberg E. A., Mahaffey J. W., Bond B. J., Davidson N. Transcripts of the six Drosophila actin genes accumulate in a stage- and tissue-specific manner. Cell. 1983 May;33(1):115–123. doi: 10.1016/0092-8674(83)90340-9. [DOI] [PubMed] [Google Scholar]
  11. Fyrberg E., Beall C. Genetic approaches to myofibril form and function in Drosophila. Trends Genet. 1990 Apr;6(4):126–131. doi: 10.1016/0168-9525(90)90127-r. [DOI] [PubMed] [Google Scholar]
  12. Fyrberg E., Fyrberg C. C., Beall C., Saville D. L. Drosophila melanogaster troponin-T mutations engender three distinct syndromes of myofibrillar abnormalities. J Mol Biol. 1990 Dec 5;216(3):657–675. doi: 10.1016/0022-2836(90)90390-8. [DOI] [PubMed] [Google Scholar]
  13. Grand R. J., Levine B. A., Perry S. V. Proton-magnetic-resonance studies on the interaction of rabbit skeletal-muscle troponin I with troponin C and actin. Biochem J. 1982 Apr 1;203(1):61–68. doi: 10.1042/bj2030061. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Hitchcock-De Gregori S. E. Study of the structure of troponin-I by measuring the relative reactivities of lysines with acetic anhydride. J Biol Chem. 1982 Jul 10;257(13):7372–7380. [PubMed] [Google Scholar]
  15. Homyk T., Jr, Emerson C. P., Jr Functional interactions between unlinked muscle genes within haploinsufficient regions of the Drosophila genome. Genetics. 1988 May;119(1):105–121. doi: 10.1093/genetics/119.1.105. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Hotta Y., Benzer S. Mapping of behaviour in Drosophila mosaics. Nature. 1972 Dec 29;240(5383):527–535. doi: 10.1038/240527a0. [DOI] [PubMed] [Google Scholar]
  17. Kobayashi T., Takagi T., Konishi K., Cox J. A. Amino acid sequence of crayfish troponin I. J Biol Chem. 1989 Jan 25;264(3):1551–1557. [PubMed] [Google Scholar]
  18. Leszyk J., Dumaswala R., Potter J. D., Collins J. H. Amino acid sequence of bovine cardiac troponin I. Biochemistry. 1988 Apr 19;27(8):2821–2827. doi: 10.1021/bi00408a024. [DOI] [PubMed] [Google Scholar]
  19. Liu H. P., Bretscher A. Disruption of the single tropomyosin gene in yeast results in the disappearance of actin cables from the cytoskeleton. Cell. 1989 Apr 21;57(2):233–242. doi: 10.1016/0092-8674(89)90961-6. [DOI] [PubMed] [Google Scholar]
  20. Maniatis T., Hardison R. C., Lacy E., Lauer J., O'Connell C., Quon D., Sim G. K., Efstratiadis A. The isolation of structural genes from libraries of eucaryotic DNA. Cell. 1978 Oct;15(2):687–701. doi: 10.1016/0092-8674(78)90036-3. [DOI] [PubMed] [Google Scholar]
  21. Poole S. J., Kauvar L. M., Drees B., Kornberg T. The engrailed locus of Drosophila: structural analysis of an embryonic transcript. Cell. 1985 Jan;40(1):37–43. doi: 10.1016/0092-8674(85)90306-x. [DOI] [PubMed] [Google Scholar]
  22. Reedy M. K., Reedy M. C. Rigor crossbridge structure in tilted single filament layers and flared-X formations from insect flight muscle. J Mol Biol. 1985 Sep 5;185(1):145–176. doi: 10.1016/0022-2836(85)90188-3. [DOI] [PubMed] [Google Scholar]
  23. Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Spradling A. C., Mahowald A. P. Identification and genetic localization of mRNAs from ovarian follicle cells of Drosophila melanogaster. Cell. 1979 Mar;16(3):589–598. doi: 10.1016/0092-8674(79)90032-1. [DOI] [PubMed] [Google Scholar]
  25. Van Eyk J. E., Hodges R. S. The biological importance of each amino acid residue of the troponin I inhibitory sequence 104-115 in the interaction with troponin C and tropomyosin-actin. J Biol Chem. 1988 Feb 5;263(4):1726–1732. [PubMed] [Google Scholar]
  26. Wegner A. Kinetic analysis of actin assembly suggests that tropomyosin inhibits spontaneous fragmentation of actin filaments. J Mol Biol. 1982 Oct 25;161(2):217–227. doi: 10.1016/0022-2836(82)90149-8. [DOI] [PubMed] [Google Scholar]
  27. Wilkinson J. M., Grand R. J. Comparison of amino acid sequence of troponin I from different striated muscles. Nature. 1978 Jan 5;271(5640):31–35. doi: 10.1038/271031a0. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press

RESOURCES