Tn10-encoded tet repressor can regulate an operator-containing plant promoter

Area of Science:

• Molecular Biology
• Plant Biotechnology
• Gene Regulation

Background:

• The Tn10-encoded tet repressor-operator system is a well-characterized prokaryotic gene regulation mechanism.
• Controlling gene expression in plants is crucial for various biotechnological applications.

Purpose of the Study:

• To investigate the functionality of the prokaryotic tet repressor-operator system in regulating transcription from the cauliflower mosaic virus (CaMV) 35S promoter in plant cells.
• To assess the potential of this system for inducible gene expression in plants.

Main Methods:

• Utilized a transient assay system with electric field-mediated gene transfer (electroporation) into tobacco protoplasts.
• Constructed a chloramphenicol acetyltransferase (cat) fusion gene under the CaMV 35S promoter, with tet operators flanking the TATA box.
• Expressed the tet repressor under eukaryotic transcription signals within the plant cells.

Main Results:

• The tet repressor effectively blocked transcription from the CaMV 35S promoter when tet operators were positioned near the TATA box.
• Addition of the inducer tetracycline restored gene expression to full activity.
• Operator location 21 base pairs downstream of the transcription start site did not significantly impair repressor function.

Conclusions:

• Demonstrated that a prokaryotic regulatory protein (tet repressor) can function effectively within plant cells.
• The tet repressor-operator complex shows promise as a tool for specifically inducing transferred genes at defined stages of plant development.