An isolated polynucleotide encoding a delayed flowering gene (DLF1) is provided, as is the isolated DLF1 protein, peptide portions thereof, and functional fragments of the DLF1. Also provided is a transgenic plant, which contains in its genome a transgene containing the polynucleotide encoding the DLF1 protein, or a nucleotide sequence complementary to the encoding polynucleotide. In addition, methods of identifying a nucleotide sequence and/or a heterologous protein that is specifically bound by the DLF1 protein, methods of using the isolated polynucleotide (or encoded polypeptide), for example, to modulate plant cell growth and/or development, are provided.