MOBILITY OF THE MAIZE TRANSPOSABLE ELEMENT EN SPM IN ARABIDOPSIS-THALIANA

The autonomous element En-1 of the maize En/Spm transposable element s ystem is capable of frequent somatic and germinal excision in the hete rologous host Arabidopsis thaliana. The pattern of En-homologous trans cripts generated in transgenic Arabidopsis resembles En transcription in maize. An excision reporter construct based on NPT-II gene (pKEn2) can be used reliably for the isolation of En-1 germinal revertants by seed germination on kanamycin-containing medium. Re-insertion after ge rminal excision is apparently frequent. A dSpm receptor element can be efficiently trans-activated in Arabidopsis either by En-1 or by expre ssing cDNAs of tnpA and tnpD. Excision and re-insertion of En/Spm take place with similar characteristics as in maize. This is the first des cription of En/Spm transposition in Arabidopsis and the parameters ana lysed here suggest that transposon tagging with En should be feasible in this species.