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Plant research reveals new role for gene silencing protein

Date:
March 29, 2012
Source:
Norwich BioScience Institutes
Summary:
A DICER protein, known to produce tiny RNAs in cells, also helps complete an important step in gene expression, according to research on Arabidopsis thaliana. The expression of a gene requires activation via a promoter or an external trigger. Plant research to be published in Science helps to show that later stages of transcription are just as important. This is likely to apply to other organisms, including humans.
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Arabidopsis.
Credit: © Olivier M. / Fotolia

A DICER protein, known to produce tiny RNAs in cells, also helps complete an important step in gene expression, according to research on Arabidopsis thaliana. The expression of a gene, when an organism's DNA is transcribed into a useable product, requires activation via a promoter or an external trigger. Plant research to be published in Science helps to show that later stages of transcription are just as important. This is likely to apply to other organisms, including humans.

Termination is the final stage of transcription. Successful termination is dependent on DNA being transcribed into RNA with the correct sections, including a certain length tail.

Scientists at the John Innes Centre on Norwich Research Park have found that where effective termination through the normal mechanisms has not occurred, DICER-LIKE 4 (DCL4) steps in to tidy up. Without termination, transcription continues down the chromosome unchecked.

In this way, DCL4 plays a crucial and previously unknown role in transcription termination. It helps formation of the gene product. DCL4 is more commonly known to play a part in the opposite effect, gene silencing.

"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.

The findings may help explain why gene silencing happens so often with transgenes. It was not known that so much attention should be given to the tail end of a gene.

"Our research shows that for successful expression the end of a gene is just as important as its beginning," said Dean.

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 that match the aberrant RNA.

"If a gene ends badly, aberrant RNA will trigger silencing pathways," said Dean.

DCL4's ability to step in to rescue poor termination makes it important for both successful gene expression, a previously unknown role for it, and gene silencing.

The research was funded by JIC's strategic funding from BBSRC and by the EU research project SIROCCO, focused on silencing RNAs


Story Source:

The above post is reprinted from materials provided by Norwich BioScience Institutes. Note: Materials may be edited for content and length.


Journal Reference:

  1. Fuquan Liu, Saleha Bakht, and Caroline Dean. Cotranscriptional Role for Arabidopsis DICER-LIKE 4 in Transcription Termination. Science, 30 March 2012: 1621-1623 DOI: 10.1126/science.1214402

Cite This Page:

Norwich BioScience Institutes. "Plant research reveals new role for gene silencing protein." ScienceDaily. ScienceDaily, 29 March 2012. <www.sciencedaily.com/releases/2012/03/120329141923.htm>.
Norwich BioScience Institutes. (2012, March 29). Plant research reveals new role for gene silencing protein. ScienceDaily. Retrieved September 2, 2015 from www.sciencedaily.com/releases/2012/03/120329141923.htm
Norwich BioScience Institutes. "Plant research reveals new role for gene silencing protein." ScienceDaily. www.sciencedaily.com/releases/2012/03/120329141923.htm (accessed September 2, 2015).

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