Insertion of non-intron sequence into maize introns interferes with splicing

Area of Science:

• Plant molecular biology
• Gene regulation
• Molecular genetics

Background:

• Transposable elements (TEs) can insert into plant genomes, potentially affecting gene function.
• Intron splicing is crucial for gene expression, and disruptions can lead to reduced protein production.

Purpose of the Study:

• To investigate how non-intron sequences inserted into plant introns impact gene splicing and expression.
• To determine if inserted sequences interfere with normal intron recognition and processing.

Main Methods:

• Chimeric introns were created by inserting non-intron sequences into maize Adh1-S intron 1 and actin intron 3.
• These constructs were tested in a maize transient expression assay using a luciferase reporter gene.
• Analysis focused on reporter gene expression levels and the presence of alternatively spliced messenger RNAs (mRNAs).

Main Results:

• Insertion of non-intron sequences into maize introns significantly decreased reporter gene expression.
• No alternatively spliced mRNAs were detected from transcripts containing the inserted non-intron sequences.
• Conversely, adding an internal intron segment restored normal splicing and efficient processing.

Conclusions:

• Non-intron sequences inserted into plant introns can negatively affect gene expression.
• These findings suggest that added non-intron sequences may interfere with the molecular machinery responsible for intron recognition and splicing.
• Understanding these interactions is crucial for predicting the functional impact of transposable element insertions in plant genomes.