FlyBase Allele Report: Dmel\Mhc[7]

General Information

Symbol

Dmel\Mhc⁷

Species

D. melanogaster

Name

FlyBase ID

FBal0012248

Feature type

allele

Associated gene

Dmel\Mhc

Associated Insertion(s)

Carried in Construct

Also Known As

Ifm(2)2

Key Links

Genomic Maps

JBrowse

Allele class

amorphic allele - genetic evidence

Mutagen

Nature of the Allele

Allele class

amorphic allele - genetic evidence

(Fyrberg et al., 1990, Beall et al., 1989)

Mutagen

Progenitor genotype

Cytology

Description

Lesion in an IFM-specific exon.

(Sandstrom et al., 1997)

Nucleotide substitution: T8914A. This changes a leucine in exon 9a to a stop codon.

(Kronert et al., 1991)

Mutations Mapped to the Genome

Curation Data

Type

Location

Additional Notes

References

point_mutation

2L:16,775,230..16,775,230 [+]

Nucleotide change:

T16775230A

Reported nucleotide change:

T8914A

Amino acid change:

L475term | Mhc-PK; L475term | Mhc-PL

Reported amino acid change:

L?term

(Kronert et al., 1991)

Variant Molecular Consequences

Associated Sequence Data

DDBJ / EMBL / GenBank

DNA sequence

Protein sequence

UniProtKB/Swiss-Prot

UniProtKB/TrEMBL

Expression Data

Reporter Expression

Additional Information

Statement

Reference

Marker for

Reflects expression of

Reporter construct used in assay

Human Disease Associations

Disease Ontology (DO) Annotations

Models Based on Experimental Evidence ( 1 )

Disease

Evidence

References

model of myopathy

CEA

(Gautam et al., 2015)

Modifiers Based on Experimental Evidence ( 0 )

Disease

Interaction

References

Comments on Models/Modifiers Based on Experimental Evidence ( 0 )

Disease-implicated variant(s)

Phenotypic Data

Phenotypic Class

abnormal flight | dominant

(Reedy et al., 2000)

flightless | dominant

(Homyk and Emerson, 1988)

viable

(Nongthomba and Ramachandra, 1999, Sandstrom et al., 1997, Kronert et al., 1991)

Phenotype Manifest In

adult somatic muscle cell

(Gautam et al., 2015)

indirect flight muscle cell

(Sandstrom et al., 1997)

indirect flight muscle cell (with Mhc^E1570K)

(Nongthomba and Ramachandra, 1999)

indirect flight muscle cell (with Mhc^L1736P)

(Nongthomba and Ramachandra, 1999)

mesothoracic tergotrochanter muscle cell

(Collier et al., 1990)

myofibril

(Beall and Fyrberg, 1991)

Detailed Description

Statement

Reference

Raman spectroscopy reveals that, as flies age, Mhc⁷ mutant muscles show characteristic abnormalities compared with wild-type controls.

(Gautam et al., 2015)

The dorsal longitudinal muscles of Mhc⁷ flies develop a fibre morphology similar to wild type.

(Nongthomba et al., 2004)

Heterozygotes have a flight impairment (flight index is 0.1 +/- 0.4 compared to 5.6 +/- 1.1 for wild-type).

(Reedy et al., 2000)

Mhc⁷ interacts with Mhc^E1570K or Mhc^L1736P in trans to give muscle phenotypes that are intermediate between the two or show severe indirect flight muscle degeneration.

(Nongthomba and Ramachandra, 1999)

The IFM contain no thick filaments (all other muscles are unaffected) and DVM shortening occurs normally suggesting this occurs independently of sliding filament-based muscle contraction.

(Sandstrom et al., 1997)

Pseudomyofibrillar arrays of thin filaments and Z discs run continuously through the sarcoplasm.

(Beall and Fyrberg, 1991)

The indirect flight muscles lack thick filaments. The small cells of the jump muscle have many fewer thick filaments than wild-type.

(Kronert et al., 1991)

Mhc accumulation in leg muscles is unaffected and the effect on thick filament accumulation in the jump muscle is less severe then Mhc¹⁰.

(Collier et al., 1990)

No thick filaments are present in Mhc⁷ homozygotes. In Mhc⁷; Act88F⁶ double homozygotes mitochondria and nuclei are the only recognizable organelles, thick and thin filaments are needed for sarcomere order and periodicity. Flight muscle defects are due to an imbalance in actin and myosin accumulation. Heterozygotes have shorter sarcomeres than wild type: filament stoichiometry influences sarcomere length determination.

(Beall et al., 1989)

Hemizygotes and heterozygotes are fully viable, flightless and have a normal wing posture.

(Homyk and Emerson, 1988)

Indirect flight muscles accumulate little or no MHC, have no thick filaments, and show no organized myofibrils. The four smaller cells of the tergal depressor of the trochanter muscle (TDT) display reduction in thick filament number and myofibril size; large TDT cells unaffected. Flies jump 33% as well as wild type. Leg muscle MHC found in normal amounts (O'Donnell, Collier, Mogami and Bernstein, 1989). homozygous viable

External Data

Linkouts

Interactions

Show genetic interaction network for Enhancers & Suppressors

Phenotypic Class

Suppressed by

Statement

Reference

Mhc⁷ has abnormal flight | dominant phenotype, suppressible by Act88F⁶/Act88F[+]

(Reedy et al., 2000)

NOT suppressed by

Statement

Reference

Mhc⁷ has abnormal flight | dominant phenotype, non-suppressible by fln⁰/fln[+]

(Reedy et al., 2000)

Suppressor of

Statement

Reference

Mhc[+]/Mhc⁷ is a suppressor of abnormal flight | dominant phenotype of Act88F⁶

(Reedy et al., 2000)

Phenotype Manifest In

Suppressor of

Statement

Reference

Mhc⁷ is a suppressor of dorsal longitudinal indirect flight muscle cell phenotype of Act88F⁶

(Nongthomba et al., 2004)

Other

Statement

Reference

Mhc⁷, wupA^hdp-3 has striated muscle thin filament phenotype

(Beall and Fyrberg, 1991)

Mhc⁷, wupA^hdp-4 has striated muscle thin filament phenotype

(Beall and Fyrberg, 1991)

Mhc⁷, wupA^hdp-5 has striated muscle thin filament phenotype

(Beall and Fyrberg, 1991)

Additional Comments

Genetic Interactions

Statement

Reference

In double homozygote Act88F⁶/Mhc⁷ mutants, dorsal longitudinal muscle fibres appear no different from in wild-type flies.

In the thorax of wupA^hdp-3/Y; Mhc⁷/Mhc^2B flies there is an absence of myofibrils and no clear areas of interdigitated thick-thin filaments. There are visible "tiger-tail" structures formed by condensed serially repeated Z-discs connected by short stretches of thin filaments.

(Nongthomba et al., 2004)

One copy of fln⁰ does not restore the flight ability of Mhc⁷ heterozygotes (flight index of double heterozygotes is 0.3 +/- 0.6). Act88F⁶ Mhc⁷ double heterozygotes have a flight index of 3.3 +/- 1.2.

(Reedy et al., 2000)

In wupA^hdp-2;Mhc⁷ double mutants the flight muscles appear normal and do not degenerate. Muscles of 5 day old wupA^hdp-3;Mhc⁷, wupA^hdp-4;Mhc⁷ or wupA^hdp-5;Mhc⁷ double mutants show a reduction in the thin filament/Z-disc network. There is a profound paucity of thin filaments.

(Beall and Fyrberg, 1991)

Xenogenetic Interactions

Statement

Reference

Complementation and Rescue Data

Comments

Images (0)

Mutant

Wild-type

Stocks (0)

Notes on Origin

Discoverer

Mogami.

Comments

Exons 15a and 15b have been sequenced and are wild-type.

(Collier et al., 1990)

External Crossreferences and Linkouts ( 0 )

Synonyms and Secondary IDs (4)

Reported As

Symbol Synonym

Ifm(2)2

(Qiu et al., 2005, Clayton et al., 1998, Ruiz et al., 1998, Vigoreaux, 1994, Beall and Fyrberg, 1991, Vigoreaux et al., 1991, Fyrberg and Beall, 1990, Fyrberg et al., 1990, Beall et al., 1989, Fyrberg et al., 1988, Homyk and Emerson, 1988)

Mhc⁷

(Gautam et al., 2015, Vikhorev et al., 2010, Patel and Saide, 2005, Qiu et al., 2005, Clayton et al., 1998)

ifm(2)2

(Patel and Saide, 2001)

Name Synonyms

myosin heavy chain7

(Gautam et al., 2015)

Secondary FlyBase IDs

References (28)

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