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Gene expression assays for actin, ubiquitin, and three microsatellite-encoding genes in Helianthus annuus
Sreepriya Pramod1, Katharyn E Downs, Mark E Welch
1Department of Biological Sciences, Mississippi State University, 212 Harned Hall, 295 Lee Boulevard, Starkville, Mississippi 39762, USA. sp456@msstate.edu
Premise Of The Study:
The "tuning knob" model of King et al. (Endeavor 21: 36-40, 1997) postulates that microsatellite mutations can alter phenotypes in a stepwise fashion. Some proposed mechanisms involve regulation of gene expression. To study the effect of microsatellites harbored in untranslated regions on gene expression in Helianthus annuus, we have developed TaqMan assays for three microsatellite-encoding genes, and two constitutively expressed genes, actin and ubiquitin, to serve as standards.
Methods And Results:
All five TaqMan assays yielded strong log-linear relationships between cycle threshold (C(T)) values and cDNA concentrations (R(2) = 0.98-0.99). Standard curves were based on five concentrations for each of five individuals. Efficiencies ranged from 0.83 to 1.03.
Conclusions:
The developed tools will allow for relative quantification of gene expression across individuals. Genotyping these loci will allow for testing the "tuning knob" hypothesis. Further, the actin and ubiquitin assays should be generally applicable to gene expression studies in H. annuus.
