Arabidopsis thaliana TOR AtTOR)gene expression at the post-transcriptional level has been studied through established and transformed Three chimeric constructs in Nicotiana benthamiana leaves and Arabidopsis thaliana plants. The first construct (the positive control) contains the AtTOR promoter, the 5¿UTR, the first intron, and the beginning of the second exon fused to the GUS reporter gene. The second construct (mutated uORF) has the same sequence as the positive control construct except the start codon of uORF was changed from ATG to TTG. The third construct (deleted 5¿UTR) has the same sequence as the positive control construct without the 5¿UTR. These constructs have also been placed under the activity of CaMV 35S promoter to investigate whether there is a link between the 5¿UTR/ or uORF and the promoter. Our work shows an overall negative regulation exerted by the 5¿UTR and, to a lesser extent, by the uORF on AtTOR gene regulation. This regulation is likely at the level of transcription or mRNA stability.