Abstract
5-Bromodeoxyuridine (BrdU), a thymidine analog, exerts promotive and inhibitory effects on shoot regeneration in hypocotyl tissue culture of Arabidopsis when administered during dedifferentiation at low and high concentrations, respectively. bro1 and bro2 are mutants resistant to BrdU with respect to these effects. bro2 is also resistant to fluorodeoxyuridine (FdU), another thymidine analog, while bro1 is not. bro1 carries a missense mutation in a gene encoding an RNA-binding protein, and bro2 carries a missense mutation in a gene encoding a thymidine kinase.
Here we report new BrdU-resistant mutants, bro3 and bro4. bro4 was shown to be resistant to FdU like bro2, while bro3 was not resistant to FdU like bro1. Chromosome mapping located these mutations on different regions of chromosome 4. Four nucleoside transporter genes, including FUR1, exist in the region where bro4 was mapped. Sequencing analysis of the bro4 genome is underway with a special note on these genes.
