Gene expression comparision in the developing striatum between transgenic rats expressing full-length human mutant huntingtin and time-matching controls

The mechanisms involved in the pathogenesis of HD that result in late, and fatal, neurodegeneration are still not fully understood. The monogenic nature of HD is in contradiction with the complexity of the cellular alterations found in patients with HD. Huntingtin interacts with a broad range of proteins within the cell, and it is altered by the expanded polyglutamine tract. Transcriptional dysregulation is a common finding in genetic models and in human HD patients, and it is thought to play an important role in the disease. Although the onset of the disease is late in life, growing lines of evidence suggest that mHtt causes alterations in development. In this microarray study, the effects of mHtt on the transcriptome were investigated with a full-length human huntingtin (96 CAG repeats) expressing transgenic rat model of HD at an early stage of development (E14). Aiming to reveal early transcriptional changes in transgenic embryos, we used Affymetrix GeneChip Rat Gene 1.0 ST Arrays to determine genome-wide expression profiles of transgenic and WT E14 ganglionic eminences. For this purpose, the cycles were synchronized, and time-bred transgenic rats were sacrificed on E14 in order to obtain time-matched transgenic and WT ganglionic eminences. Six BACHD+/+ and six WT transgenic ganglionic eminences were used, derived from three time-bred transgenic dams dissected on the same day. Genotyping was performed at both the genomic and transcriptional levels, in order to ensure accurate genotype determination.