
Science Resources RSS Feeds
|
 |
 |
 |
Short RNAs show a long history
October 02, 2008
MicroRNAs, the tiny molecules that fine-tune gene expression, were first discovered in 1993. But it turns out they've been around for a billion years. Evidence reported in Nature on October 1 by scientists in the lab of Whitehead Member and Howard Hughes Medical Institute investigator David Bartel provides a window into the early evolution of these key regulators, placing their origin within the earliest of animal lineages. The research also suggests that microRNAs present early on have undergone extensive changes, which likely have altered their functions across various lineages.
"This is the first evidence that microRNAs were present within the earliest animal lineages and are not just characteristic of more complex animals," says Andrew Grimson, a postdoctoral fellow in Bartel's lab. Scientists knew that microRNAs existed within bilaterians, an evolutionary group that includes everything from worms to fruit flies to humans, he explains. "Remarkably, we discovered their presence within sponge, a member of the earliest diverging group of animals."
The scientists used high-throughput sequencing to probe samples from animals that diverged before the origin of bilaterian animals. The sponge (Amphimedon queenslandica) represents a group of animals that split off in evolution very early, whereas the starlet sea anemone (Nematostella vectensis) split off more recently.
The sequences of microRNAs within each lineage were different from each other, suggesting that microRNA functions are almost certainly very different in these different lineages. "In a relatively narrow spectrum of evolution microRNAs are often conserved," says Grimson. "But in a broader spectrum they have completely changed. This suggests that microRNA evolution is more flexible and may be evolving more rapidly than suspected."
Researchers also pinpointed piRNAs, another class of small RNAs, among these two species. Although less is known about piRNAs, they characteristically have longer sequences than microRNAs and are thought to dampen the activity of transposons-chunks of DNA that can move around the genome, causing mutations.
"It appears that both microRNAs and piRNAs have been available to shape gene expression throughout the evolution of animals and perhaps even helped to usher in the era of multicellular animal life," says Bartel.
Whitehead Institute for Biomedical Research
|
 |

|
MicroRNAs: From Basic Science to Disease Biology
by Krishnarao Appasani (Editor), Sidney Altman (Editor), Victor R. Ambros (Editor)
MicroRNAs (miRNAs) are RNA molecules, conserved by evolution, that regulate gene expressions and their recent discovery is revolutionising both basic biomedical research and drug discovery. Expression levels of MiRNAs have been found to vary between tissues and with developmental stages and hence evaluation of the global expression of miRNAs potentially provides opportunities to identify regulatory points for many different biological processes. This wide-ranging reference work, written by leading experts from both academia and industry, will be an invaluable resource for all those wishing to use miRNA techniques in their own research, from graduate students, post-docs and researchers in academia to those working in R&D in biotechnology and pharmaceutical companies who need to understand...
|

|
microRNA: Biology, Function & Expression (Nuts & Bolts series)
by Neil J. Clarke; Philippe Sanseau (Author)
Providing a comprehensive overview of a fast-emerging field, this volume dedicated to the biological role of microRNAs (miRNAs) discusses methods for identifying and characterizing their functions and looks at potential applications of microRNA research in medicine and pharmacology. miRNAs are small, noncoding RNA molecules that appear to regulate gene expression. Found in plant and animal species and possibly traceable back to ancient forms of life, miRNAs are now estimated to regulate a third or more of genes in the human genome. The Editors have included material from some of the very best, most active and upcoming researchers in the field, to provide the reader with a rounded overview of the biology, function and expression of miRNAs. The chapters are grouped according to the...
|

|
MicroRNA Interference Technologies
by Zhiguo Wang (Author)
MicroRNAs (miRNAs), endogenous noncoding regulatory mRNAs of around 22-nucleotides long, have rapidly emerged as one of the key governors of the gene expression regulatory program in cells of varying species, with ever-increasing implications in the control of the fundamental biological processes and in the pathogenesis of adult humans. The exciting findings in this field have inspired us with a premise and a promise that miRNAs will ultimately be taken to the heart for therapy of human disease. While miRNAs have been considered potential therapeutic targets for disease treatment, it remains obscured what strategies we can use to achieve the goal. In the past years, we have witnessed a rapid evolving of many creative, innovative, inventive strategies and methodologies pertinent to...
|

|
MicroRNA Protocols (Methods in Molecular Biology)
by Shao-Yao Ying (Editor)
MicroRNA Protocols provides diverse, novel, and useful descriptions of miRNAs in several species, including plants, worms, flies, fish, chicks, mice, and humans. These include some useful adaptations and applications that could be relevant to the wider research community who are already familiar with the identification of miRNAs. This volume will stimulate the reader to explore diverse ways to understanding the mechanism in which miRNAs facilitate the molecular aspects of the biomedical research.
|

|
Microrna Profiling in Cancer: A Bioinformatics Prospective
by Yuriy Gusev (Editor)
The recent discovery of microRNAs - a new class of non-coding RNAs - has revolutionized modern biomedical sciences. This book presents current advances in the emerging interdisciplinary field of microRNA research of human cancers from a unique perspective of quantitative sciences: bioinformatics, computational and systems biology and mathematical modeling. This volume contains adaptations and critical reviews of the recent state-of-the-art studies, ranging from technological advances in microRNA detection and profiling, clinically oriented microRNA profiling in several human cancers, to a systems biology analysis of global patterns of microRNA regulation of signaling and metabolic pathways. Interactions with transcription factor regulatory networks and mathematical modeling of miRNA...
|

|
Current Perspectives in microRNAs (miRNA)
by Shao-Yao Ying (Editor)
Nearly 97 percent of the human genome is the non-coding DNA, which varies from one species to another, and changes in these sequences are frequently noticed to manifest clinical and circumstantial malfunction. Numerous non-protein-coding genes are recently found to encode microRNAs, which are responsible for RNA-mediated gene silencing through RNA interference (RNAi)-like pathways. MicroRNAs (miRNAs), small single-stranded 17-25 nucleotide RNAs capable of interfering with intracellular messenger RNAs (mRNAs) that contain either complete or partial complementarity, are useful for the design of new therapies against cancer polymorphism and viral mutation. Currently over 1000 native miRNA species found in vertebrates and many more new miRNA homologs continue to be identified; however, most...
|

|
MicroRNA Methods, Volume 427 (Methods in Enzymology)
by John J. Rossi (Editor)
MicroRNAs (miRNA) are tiny bits of genetic material that were unknown nearly 10 years ago but now represent an exciting field of study in biology. Upon their discovery, researchers revealed for the first time a new mechanism by which microRNA can stop the function of messenger RNA (mRNA) by literally cutting it in half, interfering with the normal function of specific messenger RNAs in gene expression.
This "expression" of genes that code for essential proteins is essentially what controls whether a cell turns into a liver, lung, or brain cell, for example. Understanding what activates this process - or stops it - is a key to understanding the biological process and builds a foundation for advances in medicine and other fields. This volume in Methods in Enzymology presents...
|
|
|
MicroRNAs and Cancer (Current Cancer Research)
by Carlo Croce (Editor)
The aim of this book is to reveal to a large spectrum of audience including biologists and physicians the extent of the microRNAs revolution in the cancer society. Alterations in miRNA genes play a critical role in the pathophysiology of many, perhaps all, human cancer: cancer initiation and progression can involve microRNAs (miRNAs) - small non-coding RNAs that can regulate gene expression. At the present time, the main mechanism of microRNAs alteration in cancer cells seems to be represented by aberrant gene expression, characterized by abnormal levels of expression for mature and/or precursor miRNA sequences in comparison with the corresponding normal tissues. Loss or amplification of miRNA genes has been reported in a variety of cancers and altered patterns of miRNA expression may...
|
|
|
Micrornas in Development and Cancer
by Frank J Slack (Editor)
MicroRNAs have recently emerged as key regulators of gene expression during development and are frequently misexpressed in human disease states, in particular cancer. These 22-nucleotide-long transcripts act to promote or repress cell proliferation, migration and apoptosis during development, all of which are processes that go awry in cancer. Thus, microRNAs have the ability to behave like oncogenes or tumor suppressors. In addition, their small size and molecular properties make them amenable as targets and therapeutics in cancer treatment. This book goes into detail on how microRNAs represent a paradigm shift in thinking about gene regulation during development and disease, and provide the oncologist with a potentially powerful new battery of agents to diagnose and treat cancer.
|

|
Plant MicroRNAs: Methods and Protocols (Methods in Molecular Biology)
by Blake C. Meyers (Editor), Pamela J. Green (Editor)
MicroRNAs constitute a particularly important class of small RNAs given their abundance, broad phylogenetic conservation and strong regulatory effects, with plant miRNAs uniquely divulging their ancient evolutionary origins and their strong post-transcriptional regulatory effects. In Plant MicroRNAs: Methods and Protocols, experts in the field present chapters that focus on the identification, validation, and characterization of the miRNA class of RNAs, and address important aspects about heterochromatic small interfering RNAs. In addition, the methods contained in this volume emphasize miRNA analyses, but also include ways to distinguish one class of small RNAs from another. As a volume in the highly successful Methods in Molecular Biology™ series, chapters include brief...
|
|