|Wirtz, Uwe - USDA/UCB PGEC|
|Obsorne, Brian - USDA/UCB PGEC|
Submitted to: Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 1, 1997
Publication Date: January 1, 1997
Citation: Wirtz, U., Obsorne, B., Baker, B.J. 1997. Ds excision from extrachromosomal geminivirus vector DNA is coupled to vector DNA replicaiton in maize. Plant Journal 11(1):125. Interpretive Summary: These results provide direct evidence for a coupling of Ds excision from extrachromosomal vector DNA to vector DNA replication in maize.
Technical Abstract: Analysis of transposition products generated after Activator (Ac) excision from the P locus in maize suggest that Ac excises either during or after replication of the P locus. The frequency of excision of the non-autonomous Ac derivative, Dissociation (Ds), from extrachromosomal replicating and nonreplicating vector DNAs in transfected black mexican sweet maize protoplasts was compared to assess directly a role of extrachromosomal vector DNA replication in Ds excision. Replicating (rep+) and nonreplicating (rep-) vector DNAs comprised a Ds element that harbored a geminivirus, wheat dwarf virus (WDV), origin of replication and WDV genes required for viral DNA replication (rep-) or mutant, inactive derivatives of these genes (rep+). Excision of Ds was detected only in those cell nuclei co-transfected with the replicating Ds-vector DNA and a transposase expression vector. Quantitative reconstruction experiments showed that Ds excised at least 3 times 10-5-fold more frequently from replicating vector DNA as compared with nonreplicating vector DNA. Therefore, these results provide direct evidence for a coupling of Ds excision from extrachromosomal vector DNA to vector DNA replication in maize.