The contractile mechanism of insect fibrillar muscle

Pringle, J. W. S.

doi:10.1016/0079-6107(67)90003-x

Cited by 192 publications

(88 citation statements)

References 51 publications

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“…A stretch of just 1-3% in muscle length triggers a large amplitude, delayed rise in tension. This is the underlaying mechanism that allows wingbeat frequencies of up to 300 Hz in Drosophila and higher in other flying insects (Pringle, 1967). IFM are regulated by both thick and thin filaments.…”

Section: Introductionmentioning

confidence: 99%

Functional recovery of troponin I in a Drosophila heldup mutant after a second site mutation.

Prado

Canal

Barbas

et al. 1995

MBoC

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To identify proteins that interact in vivo with muscle components we have used a genetic approach based on the isolation of suppressors of mutant alleles of known muscle components. We have applied this system to the case of troponin I (TnI) in Drosophila and its mutant allele heldup2 (hdp2). This mutation causes an alanine to valine substitution at position 116 after a single nucleotide change in a constitutive exon. Among the isolated suppressors, one of them results from a second site mutation at the TnI gene itself. Muscles endowed with TnI mutated at both sites support nearly normal myofibrillar structure, perform notably well in wing beating and flight tests, and isolated muscle fibers produce active force. We show that the structural and functional recovery in this suppressor does not result from a change in the stoichiometric ratio of TnI isoforms. The second site suppression is due to a leucine to phenylalanine change within a heptameric leucine string motif adjacent to the actin binding domain of TnI. These data evidence a structural and functional role for the heptameric leucine string that is most noticeable, if not specific, in the indirect flight muscle. INTRODUCTIONThe regulation of contraction in striated muscle occurs by mechanisms that are remarkably similar throughout the animal kingdom. Nerve input results in the

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Section: Introductionmentioning

confidence: 99%

Functional recovery of troponin I in a Drosophila heldup mutant after a second site mutation.

Prado

Canal

Barbas

et al. 1995

MBoC

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“…This muscle has evolved many special fea tures (Shafiq 1963a,b;Smith 1963;Garamvolgyi 1965a,b;Peristianis and Gregory 1970;Cullen 1974;Crossley 1978) that allow it to produce high wing beat frequencies. The IFM also is unique because it displays asynchronous contraction, where a single burst from motor neurons causes activation that is maintained by rapid changes in length and tension, resulting from the mechanical properties of the muscle (Nachtigal and Wilson 1967;Pringle 1967;Thorson and White 1969;Tregear 1975). The IFM is called fibrillar because the muscle cells contain large numbers of discrete cylin drical myofibrils that can be teased individually away during dissection.…”

Section: Muscle Diversity and The Generation Of Mhc Isoforms In Drosomentioning

confidence: 99%

Ultrastructural and molecular analyses of homozygous-viable Drosophila melanogaster muscle mutants indicate there is a complex pattern of myosin heavy-chain isoform distribution.

O'Donnell¹,

Collier²,

Mogami³

et al. 1989

Genes Dev.

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We describe the ultrastructural and initial molecular characterization of four homozygous-viable, dominantflightless mutants of Drosophila melanogaster. Genetic mapping indicates that these mutations are inseparable from the known muscle myosin heavy-chain (MHC) allele Mhc^, and each mutation results in a muscle-specific reduction in MHC protein accumulation. The indirect flight muscles (IFMs) of each of these homozygous mutants fail to accumulate MHC, lack thick filaments, and do not display normal cylindrical myofibrils. As opposed to the null phenotype observed in the IFM, normal amounts of MHC accumulate in the leg muscles of three of these mutants, whereas the fourth mutant shows a 45% reduction in leg muscle MHC. The ultrastructure of the tergal depressor of the trochanter muscle (TDT, or jump muscle] is normal in one mutant, completely lacks thick filaments in a second mutant, and displays a reduction of thick filaments in two mutants. The thick filament reduction in this latter class of mutants is limited to the four smaller anterior cells of the TDT, indicating that the TDT is a mixed fiber-type muscle. Because all isoforms of muscle MHC are encoded by alternative splicing of transcripts from a single gene, our results suggest that there is a complex pattern of MHC isoform accumulation in Drosophila, The phenotypes of the homozygous-viable mutants provide evidence for the differential localization of MHC isoforms in different muscles, within the same muscle, and even within a single muscle cell. The mutant characteristics also suggest that the use of some alternative exons is shared among the IFM, TDT, and additional muscles whereas the use of others is unique to the IFM.[Key Words: Drosophila-, muscle mutants; myosin heavy chain; alternative RNA splicing]

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“…ADP, orthophosphate and H+, are of particular interest in this context, as these components may be presumed to affect the cross-bridge cycling rate and therefore the maximum speed of shortening. ADP has been shown to reduce the rate of ATP splitting in myosin and actomyosin solutions of mammalian (Nanninga, 1962) and insect muscles (Pringle, 1967, and for further references). Lowering the pH from 8-0 to 6-0 has similarly been found to inhibit the calcium activated ATPase activity of myofibrils in suspension (Schiidler, 1967;Bendall, 1969;Portzehl, Zaoralek & Gaudin, 1969).…”

Section: Segmental Differences In Shortening Velocity Along Muscle Fimentioning

confidence: 99%

Differences in maximum velocity of shortening along single muscle fibres of the frog.

Edman¹,

Reggiani²,

Kronnie³

1985

The Journal of Physiology

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SUMMARY1. The velocity of 'unloaded' shortening (VO) and the force-velocity relation were studied during fused tetani (0-5-2-0 TC) in short successive segments along the entire length of single fibres isolated from the tibialis anterior muscle of Rana temporaria. The segments were defined by opaque markers of hair that were placed on the fibre surface, 0-5-0 8 mm apart, from one tendon insertion to the other. The change in distance between two adjacent markers (one segment) was monitored by means of a photoelectric recording system, while the fibre was released to shorten isotonically between 2X2 and 2-0 gsm sarcomere lengths. The accuracy of the V0 measurement was better than 4 % in all parts of the fibre.2. V0 varied along the length of the fibre, each fibre having a unique velocity pattern that remained constant throughout the experiment. The difference between the highest and lowest values of V0 within the fibre varied between 11 and 45 % of the fibre mean in thirty-two preparations (mean difference 23 + 2 %, S.E. of mean).3. An attempt was made to relate the V0 pattern to the fibre's orientation in the body in fourteen complete experiments. The highest values of VI were obtained near the proximal end ofthe fibre, and there was a clear trend for V0 to assume lower values towards the distal end.4. The V1 pattern along the fibre did not correlate with the segments' capacities to produce force nor with the passive viscoelastic properties of the segments.5. Force-velocity data obtained from individual segments provided a good fit to Hill's (1938) 6. The results support the view that the kinetic properties of the myofilament system differ from one region to another along the length of a muscle fibre.

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The contractile mechanism of insect fibrillar muscle

Cited by 192 publications

References 51 publications

Functional recovery of troponin I in a Drosophila heldup mutant after a second site mutation.

Functional recovery of troponin I in a Drosophila heldup mutant after a second site mutation.

Ultrastructural and molecular analyses of homozygous-viable Drosophila melanogaster muscle mutants indicate there is a complex pattern of myosin heavy-chain isoform distribution.

Differences in maximum velocity of shortening along single muscle fibres of the frog.

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