TwoStabiliserloci inAntirrhinumsuppress the transposition of Tam3 without compromising transposase production

Abstract

AbstractAntirrhinum majushas been known to exhibit occasional instabilities that are manifested as variegations and morphological chimeras.Stabiliser(St) is a historical locus that stabilizes phenotypically unstable or mutable traits inAntirrhinum. Here, we characterized twoStloci, the previously describedOld Stabiliser(OSt) andNew Stabiliser(NSt), inAntirrhinumthat specifically suppress the transposition of the Class II DNA transposable element, Tam3. BothStloci involve derivatives of Tam3 with unique structures:OSthas a pseudo-Tam3 copy whose 5’-terminal region has been rearranged compared to the cognate Tam3 element, andNStconsists of two intact copies of Tam3 in a head-to-head orientation. Neither locus interferes with the production of the intact Tam3 transposase (TPase) or the nuclear import of TPase.BothOStandNStproduce specific sRNAs from their 5’ terminal regions containing multiple TPase binding motifs. These specific sRNAs could repress Tam3 transposition by interacting with the TPase binding motifs within the Tam3 element or with the TPase itself.