Table 4.

Drosophila models of Huntington’s disease.

Drosophila Model	Developmental Stage	Assay Used for Neuropathology	References
Huntington’s Disease
Drosophila orthologs of human genes
Fly dHtt does not express polyQ in its N–terminus	N/A	N/A	[141]
Overexpression of human transgenes
Transgenic expression of a Q48 peptide or Htt Exon1p in neurons	Adult	Lifespan, photoreceptor morphology count	[144]
Transgenic expression of various Q48 constructs	Adult	Locomotor, photoreceptor morphology count	[151]
Transgenic expression of Q108 and Q48 peptides, transgenic expression of bivalent polyQ peptides	Adult	Lifespan, photoreceptor morphology count	[152]
Expression of Q127 and Q20 peptides	Adult	SEM and light microscopy for retina morphology, light microscopy for pigmentation defects, staining with FITC for presence of polyQ aggregates	[153]
Expression of mRFP–tagged N–terminal fragments of human Q15 or Q138 peptides	Adult	Lifespan, locomotion, activated–Caspase 3 immunostaining, immunostaining for brain size	[148]
Expression of an mRFP–tagged N–terminal fragment of human Q15 or Q138 peptides containing exons 1–12	Adult	Immunofluorescence for spreading of Huntingtin aggregates in the brain	[25]
Expression of several 3– or 1–exon sections of mutant Htt with various polyQ lengths in clock neurons and ventral lateral neurons (sLNvs), RNAi knockdown of heat shock protein (Hsp)	Adult	Htt–eGFP fusions to track and quantify aggregation, sLNv count, rhythmicity, confocal imaging for PER protein intensity, transcript levels of Hop–associated proteins	[145]
Expression of Q93 and Q20 peptides	Adult, Larva	Adult: locomotion Larva: crawling assay	[146]
Temperature–inducible expression of a Q15 or Q138 12–exon fragment of the human Htt gene, or expression of a 548 amino acid Q0 or Q128 segment of human Htt	Adult, pharate adult, larva	Adult: RFP tag for imaging of Htt aggregation and localization Pharate adult: lethality Larvae: viability past 2nd instar for small molecule screen, Fluorescence recovery after photobleaching for aggregate growth	[142]
Expression of full–length Q128 or Q16 human Htt	Adult, larva	Adults: Western blot for Huntingtin levels, photoreceptor morphology count, locomotion, flying assay, confocal microscopy to count neuronal projections into IFMs Larvae: immunohistochemistry for third–instar larval NMJ count, EJP amplitudes, Ca2+ imaging	[143]