Abundance of Transgene Transcript Variants Associated with Somatically Active Transgenic Helitrons from Multiple...

Area of Science:

• Genetics
• Molecular Biology
• Plant Science

Background:

• Helitrons are novel DNA transposons found in many eukaryotic genomes.
• The transposition mechanisms of Helitrons in plants remain poorly understood.
• Empirical evidence for Helitron activity in plants is limited.

Purpose of the Study:

• To genetically identify autonomous Helitrons (aHel) in maize.
• To demonstrate Helitron transposition and repair mechanisms in maize using artificial reporter systems.
• To investigate the impact of Helitron sequence features on excision and gene transcription.

Main Methods:

• Construction of artificial defective Helitron (dHel) reporter systems.
• Genetic crosses of transgenic maize lines with inbred lines and testers.
• Analysis of kernel phenotypes (purple-blotched) indicating gene expression changes.
• Transcription analysis of host gene and transgene expression.
• Detection of dHel-GFP excision products and circular intermediates.

Main Results:

• Transgenic lines produced progeny with altered kernel phenotypes due to dHel insertion.
• Helitron insertions into the C1 gene promoter/exon generated distinct mRNA transcripts.
• Excision products and circular intermediates of dHel-GFP transposition were detected in F1 hybrids.
• Reporter system successfully detected genetic activity of autonomous Helitrons at the molecular level.
• Sequence features of dHel and flanking regions influence excision and gene regulation.

Conclusions:

• The study successfully identified autonomous Helitrons in maize and elucidated their transposition and repair mechanisms.
• The developed dHel reporter system is effective for detecting Helitron genetic activity in maize.
• Helitron sequence features and flanking regions play a crucial role in regulating their activity and host gene transcription.