Cold stress is one of the most severe environmental conditions which cause huge losses in crop production worldwide. We identified a DEAD box RNA helicase, RCF1 (Regulator of CBF gene expression 1) that controls pre-mRNA splicing of cold-stress-responsive genes including positive and negative regulators of CBF genes. We used whole genome tiling array analysis under normal growth conditions to identify transcripts which are mis-spliced/intron-retained in rcf1-1. Fourteen-day-old wild type and rcf1-1 seedlings grown on MS agar medium (1x MS salts, 2% sucrose, 0.6% agar, pH 5.7) under normal conditions were harvested for total RNA isolation. RNA was extracted with Trizol reagent (Invitrogen) and synthesized into double-stranded DNA that was hybridized to whole genome tiling arrays (Affymetrix Arabidopsis Tiling1.0R). All hybridizations were performed with 3 biological replicates.