Ubiquitination pathway is a way of protein modification after translation, which plays important roles in abiotic stress and hormone-singal sensing. E3 ligases confer specificity to ubiquitination by recognizing target substrates and mediating transfer of ubiquitin from an E2 ubiquitin conjugating enzyme to substrate. In this work, we studied the expression and function of AtTR1 (At3g47550), which shares 86% to its homologues in Brassica napus (BnTR1). In vitro self-ubiquitination assay demonstrated that the RINGv domain protein possess an E3 ligase activity. The analysis of expression pattern revealed that AtTR1 was dominantly accumulated in plant tissues and highly induced by salt (200mmol NaCl). The result indicated a specific role of AtTR1 in adaptation to salt stress. In addition, AtTR1 was cloned with PCR and constructed on the plant expression Vector pZH01. RT-PCR analysis of hygromycin resistant plants showed that AtTR1 gene had been integrated into the genome of attr1 mutant. These results provided important information for studying biological functions of AtTR1.
