| Abstract Detail
Epigenetics Luo, Zhenghua [1], Chen, Zhixiang [2]. Effects of the Transgene Size on Transgene Expression in Transgic Plants. A key step in expression genes including transgenes is transcription. Up until recently, it has been widely believed that regulation of transcription occurs at early stages such as preinitiation and initiation while transcription elongation has been thought of as the trivial addition of ribonucleoside triphosphates to the growing mRNA chain. Studies over last several years have made it apparent that transcription elongation is an important stage of transcription capable of coordinating downstream events including pre-mRNA capping, splicing, 3΄ end processing, surveillance and export. Defects in pre-mRNA processing of transgenes can lead to production of aberrant RNAs capable of triggering RNA-dependent RNA polymerase (RdRP)-mediated RNA silencing in Arabidopsis. We have recently discovered that consistent RNA silencing induced by a transgene construct with three direct repeats of b-glucuronidase (GUS) open reading frame (ORF) was associated with production of high levels of truncated, unpolyadenylated transcripts most likely resulting from abortive transcription elongation of the unusually long transgene construct. To further analyze the effects of the transgene size on transcript elongation and RNA silencing of transgenes, we have transformed transgenes of different sizes driven by the enhanced CaMV 35S promoter into both wild type and silencing-deficient rdr6 mutant plants. Transcript accumulation and RDR6-dependent silencing of the transgenes of different sizes will be analyzed and compared in the transgenic plants and the results will be presented.
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1 - Purdue University, Botany and Plant Pathology, Lily Hall of Life Sciences, 915 W. State Street, West Lafayette, IN, 47907-2054, USA
2 - Purdue University, Botany and Plant Pathology
Keywords:
transgene size
transgene expression.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P38004
Abstract ID:1416 |
