ARABIDOPSIS-THALIANA RAD6 HOMOLOG ATUBC2 COMPLEMENTS UV SENSITIVITY, BUT NOT N-END RULE DEGRADATION DEFICIENCY, OF SACCHAROMYCES-CEREVISIAERAD6 MUTANTS

AtUBC2 of Arabidopsis thaliana encodes a structural homolog of the RAD 6 gene of Saccharomyces cerevisine with approximately 65% identical am ino acids. Like structural homologs from other organisms, AtUBC2 lacks the carboxyl-terminal extension of mostly acidic amino acids which is present in Rad6p. AtUBC2 was expressed in S. cerevisine rad6 mutants. It was found to partially complement the UV sensitivity and reduced g rowth rate of rad6 mutants at elevated temperatures. AtUBC2 however, h as no apparent influence on the degradation of N-end rule substrates i n the heterologous host.