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Flatworm genes may provide insights into human diseases, researchers say
December 14, 2005Could vital information about many human diseases be deciphered from genes inside freshwater flatworms? A definitive yes is not the answer yet, but research at the University of Illinois at Urbana-Champaign has provided an important advance for pursuing both that idea and the biology of stem cells.
In a paper appearing on line this week ahead of regular publication in the Proceedings of the National Academy of Sciences, researchers report the sequencing and analysis of 27,161 expressed sequence tags (ESTs) of the sexually reproducing strain of the planarian Schmidtea mediterranea.
Not only were 66 percent of them similar to sequences already in public databases, the researchers found 142 of 287 genes associated with human diseases. Because the ESTs they studied represent only about one-half of the total, "it seems likely that the vast majority of human disease genes will have homologues in planarians," the scientists wrote.
"One of the striking things we found is that when we look at planarian genes, we see a group that is conserved between planarians and mammals that is not found in Drosophila or C. elegans," said Phillip A. Newmark, a professor of cell and developmental biology at Illinois. "We speculate that these conserved sequences may play roles in processes such as long-term tissue maintenance and cell turnover that are likely less important for short-lived organisms like nematodes and insects," wrote Newmark and colleagues.
Drosophila melanogaster and C. elegans (Caenorhabditis elegans) are standard model invertebrates used in biology. "The fact that they don't have some of the genes that planarians share with mammals says that planarians will be an important, complementary model for studying gene function," Newmark said.
On a more basic level, the work by Newmark and colleagues will aid the planarian genome-sequencing project being done at Washington University in St. Louis.
ESTs are short sequences of DNA produced by the reverse transcription of messenger RNA into complementary DNA. Sequencing and categorizing ESTs allow researchers to rapidly identify genes.
Previously sequenced ESTs came from asexual planarians.
Sexual planarians don't develop reproductive structures until after they've reached adulthood, when their stem cells go to work in a process known as epigenetic germ cell specification. Asexual planarians reproduce by transverse fission - by splitting into pieces and regenerating; they do not develop reproductive structures.
Both planarian strains, however, can regenerate themselves when split. By comparing the machinery of the two strains, basic knowledge about stem and germ cell activity might be enhanced, Newmark said. "Many of the genes in this collection are going to be important for studying stem cell biology and regeneration," he said.
The ESTs identified by Newmark's team came from two developmental stages of S. mediterranea. The 27,000-plus ESTs represent some 10,000 unique transcripts, or individual sequences of RNA. Of 53 genes linked to reproduction, 87 percent were expressed in reproductive organs.
University of Illinois at Urbana-Champaign
"One of the striking things we found is that when we look at planarian genes, we see a group that is conserved between planarians and mammals that is not found in Drosophila or C. elegans," said Phillip A. Newmark, a professor of cell and developmental biology at Illinois. "We speculate that these conserved sequences may play roles in processes such as long-term tissue maintenance and cell turnover that are likely less important for short-lived organisms like nematodes and insects," wrote Newmark and colleagues.
Drosophila melanogaster and C. elegans (Caenorhabditis elegans) are standard model invertebrates used in biology. "The fact that they don't have some of the genes that planarians share with mammals says that planarians will be an important, complementary model for studying gene function," Newmark said.
On a more basic level, the work by Newmark and colleagues will aid the planarian genome-sequencing project being done at Washington University in St. Louis.
ESTs are short sequences of DNA produced by the reverse transcription of messenger RNA into complementary DNA. Sequencing and categorizing ESTs allow researchers to rapidly identify genes.
Previously sequenced ESTs came from asexual planarians.
Sexual planarians don't develop reproductive structures until after they've reached adulthood, when their stem cells go to work in a process known as epigenetic germ cell specification. Asexual planarians reproduce by transverse fission - by splitting into pieces and regenerating; they do not develop reproductive structures.
Both planarian strains, however, can regenerate themselves when split. By comparing the machinery of the two strains, basic knowledge about stem and germ cell activity might be enhanced, Newmark said. "Many of the genes in this collection are going to be important for studying stem cell biology and regeneration," he said.
The ESTs identified by Newmark's team came from two developmental stages of S. mediterranea. The 27,000-plus ESTs represent some 10,000 unique transcripts, or individual sequences of RNA. Of 53 genes linked to reproduction, 87 percent were expressed in reproductive organs.
University of Illinois at Urbana-Champaign
Human Disease Current Events and Human Disease News RSSReflux esophagitis due to immune reaction, not acute acid burn, UT Southwestern researchers report
Contrary to current thinking, a condition called gastroesophageal reflux disease (GERD) might not develop as a direct result of acidic digestive juices burning the esophagus, UT Southwestern Medical Center researchers have found in an animal study.
WPI Researchers Take Aim at Hard-to-Treat Fungal Infections
A team of researchers at the Worcester Polytechnic Institute (WPI) Life Sciences and Bioengineering Center at Gateway Park has developed a new model system to study fungal infections.
Newly Discovered Fat Molecule: An Undersea Killer with an Upside
A chemical culprit responsible for the rapid, mysterious death of phytoplankton in the North Atlantic Ocean has been found by collaborating scientists at Rutgers University and the Woods Hole Oceanographic Institution (WHOI). This same chemical may hold unexpected promise in cancer research.
UM Scientists Create Fruit Fly Model to Help Unravel Genetics of Human Diabetes
As rates of obesity, diabetes, and related disorders have reached epidemic proportions in the US in recent years, scientists are working from many angles to pinpoint the causes and contributing factors involved in this public health crisis.
First draft of the pig: Researchers sequence swine genome
A global collaborative has produced a first draft of the genome of a domesticated pig, an achievement that will lead to insights in agriculture, medicine, conservation and evolution.
Common weed could provide clues on aging and cancer
A common weed and human cancer cells could provide some very uncommon details about DNA structure and its relationship with telomeres and how they affect cellular aging and cancer, according to a team led by scientists from Texas A&M University and the University of Cincinnati (UC).
Mice regain ability to extend telomeres suggesting potential for dyskeratosis congenita therapy
The human genetic disease dyskeratosis congenita (DKC) is an autosomal dominant disease that leads to abnormalities in tissues with a rapid cell turnover - the skin, nails, bone marrow, lungs and gut.
Studying cancer in pet dogs to find new treatments for human patients
A team of scientists at the National Cancer Institute (NCI) in Bethesda, USA, says that studying pet dogs with cancer could yield valuable information on how to diagnose and treat human cancers.
Jumping genes, gene loss and genome dark matter
In research published today by Nature, an international team describes the finest map of changes to the structure of human genomes and a resource they have developed for researchers worldwide to look at the role of these changes in human disease.
Fish fend off invading germs with an initial response similar to the one found in people
Since the human response to infection is highly complex, research to understand how people fight infection is facilitated by studying how similar processes occur in simpler organisms.
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