Plant research reveals new role for widespread protein
4 April 2012
Researchers looking at Arabidopsis plants have discovered a new role for a widespread protein. The protein was previously known for its importance in 'silencing' genes but it has now been shown to play an important role in terminating gene expression. The research broadens our understanding of how cells produce functional products based on the information in genes. This research could translate to many biological applications, from genetic modification to improving understanding of human health.
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. It is the first step leading to gene expression, when an organism's genetic code is transcribed into a useable product. Termination is the final stage of transcription and successful termination is dependent on DNA being transcribed into RNA with the correct sections.
New research, to be published in Science, reveals additional components are involved in terminating transcription.
Scientists at the John Innes Centre on Norwich Research Park found that where effective termination through the normal mechanisms has not occurred, a protein called DICER-LIKE 4 (DCL4) steps in to tidy up.
In this way, DCL4 plays a crucial and previously unknown role in transcription termination helping the successful formation of the required gene product.
"DCL4 is a back-up to termination processes, helping a gene to be successfully expressed," said lead author Professor Caroline Dean from JIC, which is strategically funded by BBSRC.
When termination fails a lot of aberrant RNA is made - this is degraded as part of a cell's quality control mechanism. This can have consequences for other sequences in the genome.
DCL4's ability to step in to rescue poor termination makes it important for successful gene expression.
The research was funded by JIC's strategic funding from BBSRC and by the EU research project SIROCCO, focused on silencing RNAs. It's an important research area because RNA silencing - the cell's natural ability to turn off genes - is a valuable tool which can be used to understand the function of genes and the mechanisms of cellular regulation. In future it may be possible to use RNA silencing as the basis of novel therapy for diverse diseases ranging from avian influenza to cancer.
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