CCA1 | Circadian clock associated 1

Important note about protein extractionTranscription factors are best isolated by freezing nucelar extract in liquid nitrogen after addition of extraction buffer, followed by thawing directly at 100°C heating block, not at RT. Centrifugation for 5 minutes will remove cell debris. Protein concenration is measure ad rest is frozen in liquid Nitrogen, in aliquots. Frozen samples are thawed at RT and loaded as soon as they are in liquid form, without heating. Such precautions are necessary to take to be able to detect a transcription factor using antibodies.

CCA1 (Circadian clock associated 1) encodes a transcription suppressor that overlaps with LHY in a regulatory feedback loop closely associated with the Arabidopsis circadian oscillator. Binds to evening elements in the TOC1 promoter and inhibits TOC1 transcription. CCA1 and LHY are colocalized to the nucleus and form heterodimers in vivo. CCA1 and LHY synergistically regulate the circadian rhythm of Arabidopsis.