|Feature type||allele||Associated gene||Dmel\Miro|
|Also Known As||dMiroB682|
|Map ( GBrowse )|
|Allele class||loss of function allele|
What does this section display?
This section contains items that were added to this record for each release. It currently only tracks new links between this FlyBase report and other FlyBase data classes (e.g. genes, references, stocks) or controlled vocabulary terms (e.g. GO, anatomy terms).
What does this section not display?
This section does not currently display links that were removed or gene model changes.
Click the icon below to subscribe to this FlyBase record and receive updates automatically through your feed reader.
|All updates||Click here to see a list of all updates to this record from FB2010_08 and on.|
|Nature of the Allele|
|Mutations Mapped to the Genome|
|Associated Sequence Data|
|Nature of the lesion|
Amino acid replacement: W105@.
|Phenotype Manifest In|
bouton & neuromuscular junction | larval stage
microtubule & bouton
mitochondrion & neuron | larval stage
mitochondrion & somatic muscle | larval stage
In Miro[B682] mutants the majority of mitochondria remain stranded in the neuronal soma and soma-proximal axon, whereas the distal axon and presynaptic nerve terminal are largely devoid of mitochondria. There is no evidence of NMJ degeneration or altered neuromuscular growth.
Stimulus-dependent or resting cytosolic Ca[2+] levels are not affected by the chronic lack of mitochondria in motor neuron-terminals of Miro[B682] mutants.
Mutant neuromuscular junctions show reliable homeostatic compensation (increase in quantal content) after treatment with philanthotoxin-433 for 10 minutes.
In the motor neurons of Miro[B682]/Miro[Sd32] larvae, mitochondria are largely absent from neuro-muscular junctions, and are present in reduced numbers in axons, mainly concentrated close to the ventral ganglion. The proportion of motile mitochondria is significantly reduced in these cells and, unlike in wild-type, many stationary mitochondria are not clustered. In addition, the motile mitochondria (both anterograde and retrograde) are significantly shorter than in wild-type. There is also a small but significant reduction in the proportion of mitochondria that are motile and in the rate of mitochondrial flux in the axons of in motor neurons of Miro[B682]/+ larvae.
Gross eye morphology is normal but phototaxis is defective in flies whose eyes are homozygous for Miro[B682]. Homozygous Miro[B682] larvae are small and have reduced muscles. They tend to wiggle on the spot, rather than moving forwards. Anterior segments show rhythmic contractions, but posterior segments are sluggish, sometimes paralyzed. In neurons of Miro[B682]/Miro[B682], Miro[Sd23]/Miro[B682], Miro[Sd26]/Miro[B682] or Miro[Sd32]/Miro[B682] larvae, mitochondria are retained in the cell bodies and not properly distributed to neuronal processes - most neuromuscular junctions lack mitochondria. The somatic muscles of Miro[B682]/Miro[B682] larvae also show highly abnormal distribution of mitochondria. However, the mitochondria in these animals show no structural abnormalities and have normal membrane potentials. In contrast to the effect on mitochondria, vesicle transport in the neurons of these animals is only weakly abnormal. Bouton morphology and distribution is abnormal at neuromuscular junction in Miro[B682]/Miro[B682] and Miro[B682]/Miro[Sd32] larvae. The arrangement of microtubules in the boutons of Miro[B682]/Miro[B682] larvae is also abnormal, but the actin cytoskeleton in these boutons appears normal. In Miro[B682]/Miro[B682] larvae, resting Ca2+ concentration at neuro-muscular junctions is higher than normal. In Miro[Sd32]/Miro[B682] larvae, excitatory junction potential evoked by 10Hz stimulation of neuro-muscular junctions (NMJs) starts off normal, but, unlike wild-type, rapidly decays. This phenotype is also seen in Miro[B682]/Miro[B682], Miro[B682]/Df(3R)mbc-R1 or Miro[B682]/Miro[Sd26] larvae, but not in Miro[B682]/Miro[Sd23] larvae. Prolonged 10Hz stimulation also leads to greater increases in Ca2+ concentration at NMJs than in wild-type. Miro[B682]/Miro[B682] also show a significant increase in spontaneous mini excitatory junction potentials following 10Hz stimulation of neuro-muscular junctions.
|Phenotype Manifest In|
|NOT Enhanced by|
|Complementation & Rescue Data|
|Fails to complement|
|Partially rescued by|
|Not rescued by|
Miro[Scer\UAS.cGa]; Scer\GAL4[elav-C155] rescues most of the phenotypes due to Miro[B682]/Miro[B682]: larval lethality, larval body and muscle size, distribution of mitochondria to the distal extremities of neurons, neuro-muscular junction morphology and microtubule cytoskeleton organization. None of these phenotypes are rescued by Miro[Scer\UAS.cGa]; Scer\GAL4[how-24B].
|Stocks ( 0 )|
|Notes on Origin|
|External Crossreferences & Linkouts|
|Synonyms & Secondary IDs ( 4 )|
|Secondary FlyBase IDs|
|References ( 5 )|