Tracking Expansions of Stable and Threshold Length Trinucleotide Repeat Tracts In Vivo and In Vitro Using Saccharomyces cerevisiae.

Publication date: Oct 06, 2019

Trinucleotide repeat (TNR) tracts are inherently unstable during DNA replication, leading to repeat expansions and/or contractions. Expanded tracts are the cause of over 40 neurodegenerative and neuromuscular diseases. In this chapter, we focus on the (CAG) and (CTG) repeat sequences that, when expanded, lead to Huntington’s disease (HD) and myotonic dystrophy type 1 (DM1), respectively, as well as a number of other neurodegenerative diseases. TNR tracts in most individuals are relatively small and stable in terms of length. However, TNR tracts become increasingly prone to expansion as tract length increases, eventually leading to very long tracts that disrupt coding (e.g. HD) or noncoding (e.g., DM1) regions of the genome. It is important to understand the early stages in TNR expansions, that is, the transition from small, stable lengths to susceptible threshold lengths. We describe PCR-based in vivo assays, using the model system Saccharomyces cerevisiae, to determine and characterize the dynamic behavior of TNR tracts in the stable and threshold ranges. We also describe a simple in vitro system to assess tract dynamics during 5′ single-stranded DNA (ssDNA) flap processing and to assess the role of different DNA metabolism proteins in these dynamics. These assays can ultimately be used to determine factors that influence the early stages of TNR tract expansion.

Williams, G.M., Petrides, A.K., Balakrishnan, L., and Surtees, J.A. Tracking Expansions of Stable and Threshold Length Trinucleotide Repeat Tracts In Vivo and In Vitro Using Saccharomyces cerevisiae. 06863. 2019 Methods Mol Biol (2056):

Concepts Keywords
Genome FACT
Huntington Repeated sequence
Lengths Genome
Metabolism RTT
Myotonic Dystrophy Microsatellite
Neurodegenerative Myotonic dystrophy
Neurodegenerative Diseases Genetics
Neuromuscular Diseases Trinucleotide repeat disorders
PCR Autosomal dominant disorders
Saccharomyces Cerevisiae Huntington’s disease
Vivo Branches of biology
SsDNA flap processing

Semantics

Type Source Name
disease MESH Microsatellite instability
disease MESH neurodegenerative diseases
disease MESH myotonic dystrophy
disease MESH neuromuscular diseases
pathway KEGG DNA replication

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