Precise control over protein production is important for both research, and applications. Protein control has typically been achieved via transcriptional methods of regulation, by using promoters of differing strength to manipulate mRNA abundance of target genes. However, this can lead to unpredictable results in protein, likely due to the many post-transcriptional mechanisms regulating protein output from mRNA. The regulation of mRNA stability and translation is particularly important in regulating protein made from a transcript. There is some evidence that conserved, short sequences (motifs) in the 5’UTR of transcripts can control translation and stability. This is thought to be due to the binding of RNA binding proteins (RBPs) which facilitate their regulation. In this study, I searched for 5’UTR motifs associated with high mRNA polysome-loading (a measure of translation), and long half-lives (a measure of stability). In doing so I aimed to discover motifs which improve protein production via increased mRNA stability or translation. Motifs found in the 5’UTRs of transcripts clustered by polysome association (translation) were found to be high confidence based on quality checks. However, motifs clustered by half-lives (stability) were found to be low confidence. To test the effects of discovered motifs on protein abundance, flow cytometry was optimised for use with protoplasts transiently expressing a GFP reporter. Validation tests showed this system to be sensitive enough to detect differences in protein resulting from different promoter-terminator combinations and different 5’UTRs. This suggests that the system is suitable for future testing of the discovered motifs. Interestingly, an interaction effect was observed between 5’UTRs and promoter-terminator combinations, suggesting greater complexity in the post-transcriptional regulation of protein abundance. Once understood, this regulation and sequence motifs may in the future be used to gain more sophisticated control over plant traits and responses.