Isolation of the transposable maize controlling elements Ac and Ds

Area of Science:

• Molecular Biology
• Plant Genetics
• Genomics

Background:

• The Waxy (Wx) locus in plants is crucial for starch biosynthesis.
• Controlling elements, such as Activator (Ac) and Dissociation (Ds), are mobile genetic sequences that can cause mutations.

Purpose of the Study:

• To clone and characterize restriction endonuclease fragments containing the Waxy (Wx) locus with Ac and Ds insertion mutations.
• To determine the molecular structure and relationship between Ac and Ds elements.

Main Methods:

• Cloning of restriction endonuclease fragments from Wx locus insertion mutants.
• Molecular analysis of cloned DNA fragments to identify insertion sizes and homologies.

Main Results:

• The Activator (Ac) element corresponds to a 4.3 kb insertion, while two Dissociation (Ds) elements are 4.1 kb and 2.0 kb insertions near the 3' end of the Wx transcription unit.
• The 4.1 kb Ds element shows high homology to Ac, differing by a small central deletion.
• The 2.0 kb Ds element is homologous to the terminal regions of the Ac element.

Conclusions:

• The study provides molecular evidence for the structure of Ac and Ds elements at the Wx locus.
• The findings elucidate the relationship between different Ds elements and the Ac element, contributing to understanding controlling element behavior in plants.