PT  - JOURNAL ARTICLE
AU  - Rachel J. Harding
AU  - Peter Loppnau
AU  - Suzanne Ackloo
AU  - Alexander Lemak
AU  - Ashley Hutchinson
AU  - Brittany Hunt
AU  - Alex S. Holehouse
AU  - Jolene C. Ho
AU  - Lixin Fan
AU  - Leticia Toledo-Sherman
AU  - Alma Seitova
AU  - Cheryl H. Arrowsmith
TI  - Design and characterisation of mutant and wild-type huntingtin proteins produced from a toolkit of scalable eukaryotic expression systems
AID  - 10.1101/492215
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 492215
4099  - http://biorxiv.org/content/early/2019/02/05/492215.short
4100  - http://biorxiv.org/content/early/2019/02/05/492215.full
AB  - The gene mutated in Huntington’s disease (HD) patients encodes the 348 kDa huntingtin (HTT) protein. The pathogenic HD CAG-expansion mutation causes a polyglutamine (polyQ) tract at the N-terminus of the HTT protein to expand above a critical threshold of ~35 glutamine residues. The effect of HD mutations on HTT is not well understood, in part due to difficulties in carrying out biochemical, biophysical and structural studies of this large protein. To facilitate such studies, we have generated expression constructs for the scalable production of HTT in multiple eukaryotic expression systems. Our set of HTT expression clones comprises both N and C-terminally FLAG-tagged HTT constructs with polyQ lengths representative of the general population, HD patients, juvenile HD patients as well as the more extreme polyQ expansions used in some HD tissue and animal models. These reagents yield milligram quantities of pure recombinant HTT protein, including many of the previously mapped posttranslational modifications. We have characterised both apo and HTT-HAP40 complex samples produced using this HD resource, demonstrating that this toolkit can be used to generate physiologically meaningful complexes of HTT. We demonstrate how these resources can produce sufficient material for protein-intensive experiments such as small angle X-ray scattering (SAXS), providing biochemical insight into HTT protein structure. The work outlined in this manuscript and the tools generated, lay a foundation for further biochemical and structural work on the HTT protein and its functional interactions with other biomolecules.