The nucleotide sequence of the maize controlling element Activator.

Area of Science:

• Plant genetics
• Molecular biology
• Genomics

Background:

• Transposable elements, such as Activator (Ac) in maize, are mobile DNA sequences that can change their position within the genome.
• Understanding the molecular mechanisms of transposition is crucial for comprehending genome dynamics and gene regulation in plants.

Purpose of the Study:

• To determine the complete nucleotide sequence of the maize Activator (Ac) transposable element.
• To identify potential coding regions and regulatory sequences within the Ac element.
• To elucidate the structural basis for Ac-mediated transposition.

Main Methods:

• DNA sequencing to determine the nucleotide composition of the Ac element.
• Bioinformatic analysis to identify open reading frames (ORFs) and potential regulatory sequences.
• Comparative analysis with related elements like Dissociation (Ds) to infer functional roles.

Main Results:

• The Activator (Ac) element is 4563 base pairs long with imperfect 11 bp terminal repetitions.
• Two open reading frames (ORFs) were identified, encoding polypeptides of 839 and 210 amino acids.
• The larger ORF is proposed to encode the trans-acting factor essential for Ac transposition, based on analysis of the related Ds element.

Conclusions:

• The nucleotide sequence of the maize Activator (Ac) element has been fully elucidated.
• The Ac element possesses a gene structure with two ORFs, suggesting a complex regulatory and functional organization.
• Structural insights into the Ac element provide a foundation for understanding the molecular mechanisms of plant transposable element activity.