Molecular cloning and characterization of a TRANSPORT INHIBITOR RESPONSE 1 (TIR1) from Nicotiana tabacum

Abstract

The full-length cDNA encoding a TRANSPORT INHIBITOR RESPONSE 1 (TIR1) protein, designated NtTIR1, was isolated for the first time from Nicotiana tabacum by the rapid amplification of cDNA ends (RACE) method. NtTIR1 contained a 1746-bp open reading frame encoding 581 amino acids. The deduced NtTIR1 protein, which showed high identity to TIR1 protein of other dicotyledonous plants, had a calculated mol wt of 65.2 kD and a theoretical pI value of 6.02 and was predicted to possess an F-box domain. Bioinformatic analyses revealed that the deduced NtTIR1 contained three transmembrane domains, and the predicted 3D model of NtTIR1 had a typical spatial structure of the TIR1 protein from Arabidopsis thaliana. Transcription pattern analysis revealed that the transcription of NtTIR1 was induced by IAA and ABA. Cloning of the NtTIR1 gene will enable us to further understand the molecular organization of the TIR1 and its possible function in the tobacco.