A single cis-element that controls cell-type specific expression in Arabidopsis (bioRxiv)

Multicellular organisms have different tissues that carry out diverse and specialized functions, and tissue-specific expression is the feature that gives each tissue its specific protein content. Despite its importance, the mechanisms that control spatial patterning is poorly understood. In this work, Kneřová et al. focus their investigation in the transcription factor MYB76 that is expressed specifically in bundle sheath cells. Kneřová et al. found that a seven-nucleotide portion of the MYB76 promoter is necessary and sufficient to direct tissue specific gene expression, and that oligomerization of this portion increases the expression level of the regulated transcript. The authors propose the use of this very short promoter in synthetic biology, as short promoters have the advantage of reduced silencing and leakiness or off-target expression. Driving expression of various genes speicifically in the bundle sheath cells could facilitate the control of: storage carbohydrates and ions, hydraulic conductance, transport of metabolites in and out of veins, responses to high light episodes, and lead to photosynthetic enhancements.  (Summary by Aime Jaskolowski) bioRxiv