Identification, sequence analysis and expression studies of novel anther-specific genes of Arabidopsis thaliana

Relatively little is known about pollen development at the molecular level. For the purpose of gaining understanding of the molecular control of pollen development, a number of Arabidopsis cDNA fragments were isolated using subtractive hybridizations. DNA and RNA hybridizations and sequence analyses indicate that we have isolated cDNAs representing 13 genes. Sequences for 8 of these genes are novel, while those for the remaining 5 genes have substantial similarity to genes previously reported as anther- or pollen-specific. RNA in situ hybridizations with 5 genes revealed that four of them are tapetum-specific with differing temporal expression patterns during pollen development and one is pollen-specific within the flower. Sequence analysis of full-length cDNAs showed that one of the novel genes, ATA7, encodes a protein related to lipid transfer proteins. Another gene, ATA20, encodes a protein with novel repeat sequences and a glycine-rich domain that shares a predicted structure with a known cell wall protein. The full-length ATA27 cDNA encodes a protein similar to the BGL4 beta-glucosidase from Brassica napus. The ATA27 protein is predicted to have an ER retention signal and an acidic isoelectric point, suggesting that it may be localized to the ER lumen. This may be a means of compartmentalization from its substrate(s). Our studies demonstrate that subtractive hybridizations can be used to identify previously unknown genes, which should be valuable tools for further study of pollen and anther development and function.