A novel tapetum-specific cDNA clone of rice, its corresponding gene designed as RA39, is isolated by RNA subtractive hybridization, differential screening and rapid amplification of cDNA ends. The RA39 cDNA is 1013 bp in length with an open reading frame encoding 298 amino acid residues. mRNA in situ hybridization reveals that RA39 is a tapetum-specific gene, and highly expressed at the meiosis stage of pollen mother cells. The deduced protein contains a signal peptide, a transmembrane region and a cytoplasmic tail, and is predicted to localize in endoplasmic reticulum by PSORT program. This cDNA sequence did not show significant homology to any known sequences in Genbank database. RA39 is the first gene identified to be expressed specifically in tapetal cells at the meiosis stage of pollen mother cells from cereals.
