Transcription profiling by array of Arabidopsis wild-type seedlings and either single or double knock-out mutants of LETM1 or LETM2

Arabidopsis ATH1 Genome Arrays were used to analyse changes in transcript abundance between Col-0 (wild-type) Arabidopsis seedlings and either single T-DNA insertional KO mutants of LETM1 (At3g59820)(T-DNA lines; SALK_067558C (letm1-1) and SALK_058471 (letm1-2)) or LETM2 (At1g65540) (T-DNA line; SALK_068877 (letm2-1)). Additionally, letm1 and letm2 knock out Arabidopsis lines were crossed to generate double mutants, however a double knock-out of these two genes results in an embryo lethal phenotype. Hemizygous plants were generated that were homozygous knock out for LETM1 and heterozygous knock out for LETM2, and visa versa, termed (letm1(-/-)LETM2(+/-) and (LETM1(+/-)letm2(-/-) respectively. Note that (letm1(-/-)LETM2(+/-) displays a mild developmental defective phenotype in the first 10-14 days of growth, while (LETM1(+/-)letm2(-/-) shows no phenotype. Microarray analysis was carried out on all three single homozygous knock out lines, and also on both combinations of the hemizygous mutation between the two genes, and compared with a wild-type Col-0 control to gain insight into global transcript abundance changes in these mutant lines. Arrays were performed in triplicate for each genotype, from RNA isolated from 3 independent pools of 5-10 Arabidopsis seedlings at 10 days old.