The SALK_135513 line of Arabidopsis thaliana is annotated by GenBank to have the T-DNA insertion in the fourth exon of NBR1 (At4g24690). Careful molecular analyses of the homozygous plants of SALK_135513 line indicated the place of T-DNA insertion in the fourth intron. Unexpectedly, 2 kinds of NBR1 transcripts, the wild-type and the mutated, resulting from alternative splicing events, were detected in those plants. Our findings explain the problems encountered by us with phenotypic evaluation of this line and emphasize the necessity for independent verification of the exact insertion site followed by careful expression studies when working with Arabidopsis T-DNA insertional mutants.
Keywords: At4g24690; KO, knock-out; MV, methyl viologen; NBR1; NBR1, Neighbor of BRCA1; SALK_135513; T-DNA mutant; T-DNA, transferred DNA; WT – wild-type; arabidopsis; intronic insertion; qRT-PCR, quantitative RT-PCR.; sqRT-PCR, semiquantitative RT-PCR; transcription.