Abstract
Cultured cell, GTH4, of the F1 hybrid Nicotiana gossei x N. tabacum showing hybrid lethality, induces cell death at 26 C, but not at 37 C. We isolated variant cell line GTH4S that no longer dies at 26 C. GTH4S cells did not show the burst of H2O2 at 26 C that functions as death signal in GTH4. Applications of actinomycin D to GTH4 suggested that de novo RNA synthesis at 37 C is required for death reaction at 26 C. This indicates that some genes specifically expressing in GTH4 may cause death reaction. To isolate genes involved in cell death of hybrid lethality, mRNA differential display was performed for both GTH4 and GTH4S cells cultured at 37 C. After several passages of screening and verification of the amplicons, we finally obtained a cDNA clone which expressed specifically in GTH4. The cDNA was a gene encoding ubiquitin-conjugating enzyme.
