Somatic Mutator activity expression is dependent on the strength of Cy trans-active signals in maize.

Two receptor element alleles (vp-rcy and bz-rcy) that respond to the trans-active element (Cy) controlling Mutator activity were used to analyze the strength of trans-active signals from Cy elements derived from a Mutator active line. Evidence is presented that the Mutator population tested consists mainly of a class of weak Cy elements designated as Cy:Mu. When Cy:Mu element are present in only a few copies, the strength of the combined transposition signal is weak. It is only when these active elements have a high copy number that the overall transposition signal is sufficiently strong enough to elicit a high frequency of transposition events. This study seeks to investigate the nature of the trans-active signal from Cy:Mu elements. The implication of these results for molecular studies is discussed.