The present invention relates to a method of enhancing the activity of a transcription factor in a plant comprising expressing in said plant a chimeric protein comprising a GIF moiety comprising a GIF domain or fragment thereof, and a DNA binding domain (DBD) moiety. The chimeric proteins comprise a GIF moiety comprising a GIF domain or fragment thereof, or a polypeptide with an amino acid sequence having at least 85%, preferably at least 90%, even more preferably at least 95% sequence identity to the amino acid sequence of a GIF domain or fragment thereof; and a DBD moiety comprising the DBD or plant transcription factor whose activity enhancement is intended, or a binding protein which is capable of forming a tertiary complex with the DBD or transcription factor whose activity modification and/or enhancement is intended. The invention also relates to polynucleotides and polypeptides useful in the method of the invention.