Ac transposition is impaired by a small terminal deletion

Area of Science:

• Genetics
• Molecular Biology
• Plant Science

Background:

• The P1-vv allele in maize features an Ac transposable element in the P1-rr gene, leading to variegated pericarp and cob pigmentation.
• Transposable elements, like Ac, play crucial roles in genome evolution and gene regulation.

Purpose of the Study:

• To characterize a novel maize allele, P1-vv5145, with altered pigmentation and Ac element behavior.
• To investigate the impact of modifications at the 3' end of the Ac element on its transposition activity.
• To explore the potential of P1-vv5145 as a tool for controlling Ds transposition.

Main Methods:

• Genetic crosses involving the P1-vv5145 allele and a Ds tester stock.
• Phenotypic analysis of pericarp and cob pigmentation.
• Molecular characterization of the Ac element and flanking sequences in P1-vv5145.
• Quantification of Ac excision and Ds transposition frequencies.

Main Results:

• The P1-vv5145 allele exhibits an extremely light variegated phenotype.
• A 2-bp deletion at the 3' end of the Ac element (Ac5145) and adjacent p1 intron sequence was identified.
• Ac excision from P1-vv5145 is 3800-fold less frequent than from the progenitor P1-vv allele.
• Despite reduced excision, P1-vv5145 effectively induces Ds transposition, indicating normal transposase function.

Conclusions:

• Alteration of the 3' terminal base of the Ac element significantly impairs its excision.
• The P1-vv5145 allele serves as a valuable and relatively stable source of Ac transposase for genetic experiments.
• The study provides insights into the mechanisms of Ac transposition and the formation of one-sided deletions.