Huntingtin Splicing Assay

Huntingtin protein plays an important role in Huntington's disease (HD). As an expert in neuroscience research, Creative Biolabs has accumulated extensive experience from projects. Based on the state-of-the-art technology platform, we are confident in offering quality-assured huntingtin splicing assay services to global clients.

Overview of Huntingtin

HD is an inherited autosomal-dominant neurodegenerative disorder characterized by a triad of motor, cognitive, and psychiatric features. HD typically displays onset in mid-life, with the irreversible progression of symptoms over 10-15 years. Almost all HD cases are caused by an abnormally expanded CAG repeat near the N terminus of the huntingtin gene (HTT), which leads to the production of mutant huntingtin protein (mHTT) on translation. It has now been 25 years since the identification of the genetic mutation in 1993, and intensive research efforts have described that multiple cellular pathological mechanisms are involved in the development of disease. Nearly all are driven by the presence of the mHTT protein, which is ubiquitously expressed and is thought to cause disease by a predominant toxic gain-of-function mechanism.

Fig. 1. Production of Potential Toxic Species in HD and Mechanisms for HTT Lowering. (Tabrizi, et al., 2019)

Huntingtin Splicing

The 67 exons HTT gene, featuring slightly higher expression levels in brain tissues (particularly in striatal neurons), ubiquitously encodes the HTT expression. Researchers have identified alternative splicing variants, some of which produce pathogenic, truncated HTT fragments. The first HTT exon accommodates an expansion-prone CAG stretch encoding for a poly-glutamine segment. Upon genetic instability, the number of CAG repeats increases and, once larger than ~35-37 repeats, translates to the polyQ-expanded mutant protein responsible for the HD onset. Despite the fact that HTT is conserved throughout evolution, the polyQ tail within its exon 1 is not. This suggests that HTT may have a role in the fine modulation of the wild-type HTT functions as a result of recent evolutionary achievements.

Fig. 2. The polyglutamine-expanded-flanking regions are critical factors in disease onset. (Caterino, et al., 2018)

Although barely representing 2% of the HTT structure, the exon 1-encoded fragments featuring polyQ-expansion are enough for developing Huntington’s phenotype in several model systems. Beyond the well-studied exon 1-encoded stretch, HTT features HEAT/HEAT-like motifs and helix-turn-helix repeats that are important in protein-protein recognition/interaction. This suggests that HTT works as a large scaffold for supramolecular assemblies. Analogy comparisons with other known structures of HEAT/HEAT-like proteins support these findings, which are further backed up by the extensive interaction network HTT is involved in. This network includes many cellular pathways and functions like vesicle trafficking, endocytosis, protein turnover, and cell morphology. The HEAT/HEAT-like motifs cluster into four domains, with many proteolysis susceptible PEST (proline (P)-, glutamic acid (E)-, serine (S)-, and threonine (T)-enriched sequences) interspersed in between, mostly in disordered segments. Researchers have identified several cleavage sites thus far, which is important because deleterious HTT aminoterminal fragments are mostly generated by proteolysis even though alternative aberrant splicing may also play a role.

Our Featured Huntingtin Splicing Assays

There have been too many reports showing the important roles HTT plays in HD research. Based on the comprehensive technology platform, Creative Biolabs provides a variety of methods for Huntingtin splicing assay. Our experienced specialists will help optimize your scheme and solve your problems.

• Quantitation by Fluorescence
• Quantitation by Western Blotting
• Quantitation by Polymerase Chain Reaction
• Random Lasing Detection
• Meso scale discovery-based assays

If you are interested in Huntingtin splicing assay or any other services on our website, please don't hesitate to contact us for more information.

References

1. Tabrizi, S. J.; et al. Huntingtin Lowering Strategies for Disease Modification in Huntington's Disease. Neuron. 2019, 101(5): 801-819.
2. Caterino, M.; et al. Huntingtin protein: A new option for fixing the Huntington's disease countdown clock. Neuropharmacology. 2018, 135: 126-138.