Seven zinc-finger transcription factors are expressed sequentially during the development of anthers in petunia

The development of anthers and pollen involves several stages. In an attempt to identify the transcription factors that are involved in the regulation of gene expression associated with the development of anthers, seven genes for new zinc-finger proteins that are expressed in anthers were detected using RT-PCR. Subsequent cloning and sequence analysis of the full-length cDNA clones revealed that they all encoded zinc-finger proteins of the EPF type. However, the encoded proteins were very different from each other in terms of size, number of zinc fingers (two, three and four) and the spacings between the fingers. Northern blot analysis revealed that the genes were expressed preferentially in anthers. Moreover, it was found that the seven genes were expressed transiently for short periods that corresponded to different developmental stages. It appeared that the genes were activated sequentially during the development of the anther. Considering these observations, a possible mechanism that could account for the autonomous progression of the development of the anther via a regulatory cascade of these transcription factors is discussed.