Robert Karl Stonjek
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 Posted: Fri Jul 11, 2008 4:34 pm Post subject: News: RNA emerges from DNA>s shadow |
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RNA emerges from DNA>s shadow
RNA, the transporter of genetic information within the cell, has emerged
from the shadow of DNA to become one of the hottest research areas of
molecular biology, with implications for many diseases as well as
understanding of evolution. But the field is complex, requiring access to
the latest equipment and techniques of imaging, gene expression analysis and
bioinformatics, as well as cross-pollination between multiple scientific
disciplines. This has led to a major European push to bring the field
together via a network of overlapping multidisciplinary projects,
spearheaded by the European Science Foundation (ESF) with its EUROCORES
Programme RNAQuality.
The great potential of the RNA research field to solve a variety of
fundamental problems relevant for understanding of life and predicting cures
for diseases was unleashed at the RNAQuality Programme>s first conference,
held in Granada in June 2008. As well as many European groups, the
conference was represented by leading pioneers from the US in the field, who
welcomed the new initiative as an important collaborative force.
RNA was once considered to be just the faithful messenger taking genetic
information from the genome to the ribosome, or protein factory, but that
view has been blown away by recent research. It is now known that RNA has
additional roles in regulating gene expression and as an important
structural component both in the cell nucleus and in the ribosomes.
Furthermore, errors in transcribing RNA from DNA are frequent and require a
variety of elaborate quality control mechanisms to prevent both
mis-regulation of genes, and manufacture of aberrant RNA and protein
fragments that clog up the workings of the cell, and that if unchecked can
cause a variety of disorders, including cancers.
Delegates at the conference also heard how there is great potential for
creating new compounds that manipulate the cell>s apparatus for transcribing
DNA into RNA to overcome a number of serious disorders caused by deleterious
mutations in specific genes, as opposed to problems with the RNA itself.
Jacobson also presented one of the most exciting developments, a molecule
that overcomes a common deficiency in genes that prevents their being read
right up to the end of their sequence during transcription.
Jacobson pointed out that there are about 2400 human genetic disorders
resulting from mutations that cause genes to be incompletely read, including
cystic fibrosis and muscular dystrophy. A drug based on the molecule is now
entering trials that could lead to it becoming generally available. Results
so far indicate dramatic improvements in both cystic fibrosis and muscular
dystrophy sufferers, although it is only suitable for those disorders caused
by the presence of a premature stop sign in a gene sequence, as a result of
a mutation. It does though highlight the huge therapeutic potential of the
research into RNA and its quality control.
Significant progress has been made in different aspects of RNA research over
the last decade or more, leading to the current situation where many groups
are working on different aspects of the problem. The challenge being met by
the ESF>s RNAQuality Programme is to bring these groups together, and make
Europe a much greater force in the field, according to Jim Anderson, from
Marquette University>s Department of Biological Sciences in the US.
Another important aspect of RNA research lies in the interaction between DNA
transcription, and the physical structure both of the membrane-bound cell
nucleus and the genome coiled within it. Genes are transcribed within the
nucleus and the resulting RNA molecules then emerge through small holes that
are connected to the genome by proteins called nuclear pore complexes. In
one of the presentations, Nick Proudfoot from Oxford University in the UK
explained how some genes are enhanced by being close to the nuclear pore
complex, indicating a close relationship between gene expression and nuclear
structure that must have played out through evolutionary history. Another
point to emerge from Proudfoot>s presentation was how some genes are
expressed more efficiently for a different reason, because the section of
DNA containing their sequence is coiled locally into a loop, rather than as
a branch.
Quite simply, this speeds up the transcription process of reading the gene
because the enzyme concerned, RNA Polymerase, can just keep on encircling
the loop. As Proudfoot explained, this is relevant for quality control as
well. "They may afford quality control by "telling" the polymerase it is
transcribing a bona fide gene, with a proper beginning and end," said
Proudfoot. "Otherwise the polymerase may have initiated erroneously." The
existence of a DNA ring makes it easier to identify the sequence
corresponding to a gene, and transcribe it correctly.
Source: European Science Foundation
http://www.physorg.com/news134908245.html
Posted by
Robert Karl Stonjek |
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