Transcription factor. Plays a crucial role in tapetum development. Required for male fertility and pollen differentiation, especially during the post-meiotic transcriptional regulation of microspore development within the developing anther (PubMed:12535353). Binds E-box regions in the AHL16/TEK promoter. Homodimer (Probable). Interacts with ASHR3. Mostly expressed in closed, post-meiotic buds, and, to a lower extent, in pre-meiotic buds. Detected in leaves, stems, and flowers. First observed a bud stage of 0.6-mm, shortly after microspore release from the postmeiotic tetrads. Later restricted within the tapetum, microspores and anther locule. Still visible within the haploid nuclei, each of which had migrated to the pollen cell wall prior to pollen mitosis I. Not expressed later.