Reduced Position Effect in Mature Transgenic Plants Conferred by the Chicken Lysozyme Matrix-Associated Region

Area of Science:

• Plant molecular biology
• Chromatin biology
• Transgenic plant development

Background:

• Matrix-associated regions are crucial for chromatin organization and can influence gene expression.
• The chicken lysozyme A element exhibits affinity for nuclear matrices, suggesting a role in chromatin architecture.

Purpose of the Study:

• To investigate the influence of the chicken lysozyme A element on transgene expression variability in tobacco.
• To determine if the A element affects reporter gene activity and gene expression levels.

Main Methods:

• Introduction of T-DNA constructs with the A element flanking reporter genes (GUS) in tobacco plants.
• Analysis of GUS gene activity variation in first-generation transgenic plants.
• Transient gene expression assays to assess enhancer functions.

Main Results:

• The A element significantly reduced GUS gene activity variation in transgenic tobacco.
• Average GUS activity increased slightly, but maximum expression levels remained consistent.
• The A element did not exhibit general enhancer functions, but prevented lower expression levels.
• Strongest variability reduction occurred when A elements bordered the T-DNA, leading to copy number-dependent expression.

Conclusions:

• The chicken lysozyme A element can stabilize transgene expression in plants by preventing low expression levels.
• Positioning the A element at T-DNA borders enhances its effect on expression stability.
• The A element's influence on chromatin structure contributes to predictable transgene activity.