A
cell-based screening
system and method for identifying compounds that selectively modulate the expression of CAG repeat-containing
RNA associated with spinocerebellar ataxias and related disorders. The
system comprises a human HEK293
T cell line engineered to co-express two reporter constructs: a CAG repeat-expanded polyglutamine-nanoluciferase
fusion protein with at least 60 CAG repeats, and a control firefly
luciferase with no CAG repeats. Each construct contains a unique probe-binding sequence downstream of the repeat region, enabling independent quantification via
multiplex RT-qPCR with fluorescent probes, as well as dual
luciferase assays. The
cell line is optimized for high-
throughput screening to identify therapeutic compounds that reduce pathogenic CAG repeat
RNA levels while sparing control transcripts. The invention further encompasses methods for screening, validating, and identifying candidate therapeutics for CAG expansion disorders, including spinocerebellar ataxias and Huntington's
disease.