Transient expression of heterologous RNAs using XXXX .

@entity64088 @entity2755 @entity1452
The genome of the geminivirus @entity64088 ) consists of two circular DNA molecules designated as components A and B. The A component contains the only virally-encoded function required for autonomous replication in infected plant cells. We used agroinoculation of petunia leaf discs with the A component to develop a transient expression system which permits direct examination of viral transcripts by S1 nuclease protection. The @entity1452 gene, which encodes the @entity64088 coat protein, was transcribed transiently in leaf discs after agroinoculation of @entity64088 a DNA. Synthesis of @entity1452 RNA was dependent on T-DNA transfer and @entity64088 DNA replication, demonstrating that it is a plant transcription product. The AL open reading frames of @entity64088 A were also expressed transiently in leaf discs. The ratio between @entity1452 RNA and the major leftward RNA was constant and was used to normalize @entity1452 transcription for viral DNA copy number. The bacterial genes encoding @entity2755 acetyltransferase (CAT) and beta-glucuronidase (GUS) were transiently expressed in leaf discs from the @entity1452 promoter in @entity64088 A. The levels of @entity1452 and GUS RNAs were similar in leaf discs after adjusting for viral DNA copy number, while CAT RNA was less abundant. The geminivirus transient expression system allows rapid analysis of RNAs transcribed from foreign genes and can serve as a preliminary screen in the construction of transgenic plants.
