Table 1.

Summary of Results from Yeast One-Hybrid and Yeast Two-Hybrid Assays Showing Binding Specificity and Binding Partner Interactions for the TCP Family of Plant Transcription Factors

Yeast One-HybridYeast Two-Hybrid
ProbeAT No.TCP NameTypeSite II C (TGGGCC)Site II T (TGGGCT)PhyALHYCCA1PIF3PRR1PRR3PRR5PRR7PRR9
At1g67260AtTCP1CYC/TB1±*********
254670_atAt4g18390AtTCP2CIN+±ο++οοοο
260618_atAt1g53230AtTCP3CIN++±++
257267_atAt3g15030AtTCP4CIN++++*********
247605_atAt5g60970AtTCP5CIN±
At5g41030AtTCP6PCF++
At5g23280AtTCP7PCF++
246398_atAt1g58100AtTCP8PCF
267515_atAt2g45680AtTCP9PCF++
266481_atAt2g31070AtTCP10CIN±±*********
263888_atAt2g37000AtTCP11PCF+++ο+++++++++
At1g68800AtTCP12CYC/TB1++++
259129_atAt3g02150AtTCP13CIN++
252425_atAt3g47620AtTCP14PCF±±
260371_atAt1g69690AtTCP15PCF++++
At3g45150AtTCP16PCF
250566_atAt5g08070AtTCP17CIN++++
At3g18550AtTCP18CYC/TB1++*********
248385_atAt5g51910AtTCP19PCF++
257788_atAt3g27010AtTCP20PCF±+*********
246011_atAt5g08330AtTCP21PCF++++
At1g72010AtTCP22PCF
262028_atAt1g35560AtTCP23PCF++
245774_atAt1g30210AtTCP24CIN+±*********
  • The 24 Arabidopsis TCPs were tested, and Affymetrix probe IDs are shown where available. Type refers to the class of TCP protein and is based on the founding members of the TCP family. Yeast one-hybrid assays were carried out with DNA sequences containing three copies of the classic site II sequence in tandem with either a C or a T in the last position (TGGGCC or TGGGCT). Yeast two-hybrid assays were performed to test for interactions with known components of the plant circadian clock as prey. All interactions were repeated a minimum of four times, and the strength of the interactions was graded as very strong (++), strong (+), very weak (±), or no interaction (–). For some TCP factors, consistently strong autoactivation was observed; thus, true interactions could not be determined (indicated by an asterisk). For TCP2, some autoactivation was observed when cloned into the bait vector for yeast two-hybrid assays; however, this was variable, and in some matings, interactions could be observed with LHY, PIF3, PRR1, PRR3, and PRR5 (indicated by ο).