NOZZLE encodes a novel protein related to MADS box transcription factors. SPL is the first describe Nozzle gene encodes a putative transcription factor, and has been implicated in ovule pattern formation and early microsporogenesis. 17 amino acid predicted helix region of the SPL gene product (amino acids 64?C80) is homologous to the first helix of the MADS domain. Furthermore, secondary structure analysis revealed that there is a basic region between residue 41 and 62, followed by two helix regions, 64?C85 and 211?C235. At the carboxy terminal there is a putative Myc-type helix?Cloop?Chelix dimerization domain signature.
1. T. Ito, F. Wellmer, H. Yu, P. Das, N. Ito, M. Alves-Ferreira, J. L. Riechmann, E. M. Meyerowitz, The homeotic protein AGAMOUS controls microsporogenesis by regulation of SPOROCYTELESS. Nature 430, 356 (2004)