While studying mice with a mutant gene whose counterpart causes inherited glaucoma in humans, researchers have discovered a second gene mutation that worsens the structural eye defect that causes this type of glaucoma. The newly discovered gene mutation affects production of L-DOPA. The researchers suggest that it might be feasible to prevent glaucoma by administering L-DOPA, which is used in treating Parkinson’s disease.
Scientists have discovered that the genetic mutation that causes the childhood cancer retinoblastoma routinely triggers fetal death and miscarriage in laboratory animals by disrupting the normal functions of the placenta, a finding that may force researchers to reevaluate the powerful Rb gene and the role it plays in causing cancer.
Researchers have identified a genetic factor that appears to influence anxiety in women. Combining DNA analysis, recordings of brain activity, and psychological tests, investigators at the National Institute on Alcohol Abuse and Alcoholism (NIAAA) found that Caucasian and American Indian women with the same gene variant had similarly high scores on tests that measure anxiety. These women also had similar electroencephelograms (EEG) — recordings of brain electrical activity as unique as an individual’s fingerprints — that showed characteristics of anxious temperament, further strengthening the association of this shared genetic factor with anxiety. The study appears in the current issue of the journal Psychiatric Genetics.
The first laboratory population study of genetically modified mosquitoes identifies issues that need to be faced in the task of turning mosquitoes from disease carriers into disease fighters. Scientists from Imperial College London report in Science today that populations including genetically modified mosquitoes quickly lose their test marker gene when they are bred with unmodified mosquitoes. The scientists say their results have several lessons for further work on developing GM mosquitoes, and they suggest a number of ways around the problems they have observed.
Bleeding after cardiac surgery is a major clinical problem, consuming up to 20 percent of the nation’s blood supply. Despite some understanding of the risk factors that contribute to increased blood loss, there is still considerable patient-to-patient variability. Scientists have now shown that a common genetic variation contributes to a patient’s tendency to suffer bleeding complications.
Researchers have developed a way to exploit RNA interference for the first time to silence genes in a wide variety of mammalian cells, including embryonic cells. The study will appear in the Feb. 17 edition of Nature Genetics. This new approach allows genes to be switched off by inserting short pieces of ribonucleic acid (RNA) into developing cells. It is currently being used to help researchers uncover the function of the more than 30,000 genes found in humans, as well as in animal models of important diseases.
Greater insight into human brain disease may emerge from studies of a new genetic mutation that causes adult fruit flies to develop symptoms akin to Alzheimer’s disease. “This is the first fruit fly mutant to show some of the outward, physical manifestations common to certain major human neurodegenerative diseases,” said principal investigator Michael McKeown, a biology professor at Brown University. A research team found the mutation in a gene they named “blue cheese.”
New molecular technologies are exposing unexpectedly high levels of DNA folding and complex protein-rich assemblages within the nucleus of cells that researchers say seriously challenge the textbook models. “What we are seeing suggests that there may be machinery, not yet identified, that controls the folding and the movements of enzymes that turn genes on and off,” noted one expert at the recent meeting of the American Association for the Advancement of Science.
An important discovery in modern molecular biology is that double-stranded RNA can quash the activity of specific genes in plants, animals, and fungi. In 1997, Dr. Andrew Fire of the Carnegie Institution of Washington and Dr. Craig Mello of the University of Massachusetts Medical School, and their team found that by specially designing RNA with two strands they could silence targeted genes. Their discovery, called RNA interference (RNAi) was recently patented (US Patent 6,506,559 B1), and it has been widely licensed in the U.S., Europe, and Japan.
Oncologists are testing a new technique called gene expression profiling that subtypes each breast cancer tumor by its genetic defects so that doctors can tailor their treatment to inhibit that particular tumor. The researchers believe the technique could spare millions of women from needlessly receiving toxic chemotherapy, and they are leading a national clinical trial to study gene profiling. “Currently, we have no predictive model to determine who will respond to hormonal therapies and who won’t, so we prescribe chemotherapy as a backup measure to ensure the cancer’s demise,” said Matthew Ellis, M.D., Ph.D., director of the breast cancer program at Duke. “This one-treatment-fits-all approach leads to a huge amount of over treatment, with up to 50 percent of women unnecessarily receiving chemotherapy.”
An international team of researchers has used a gene test to identify certain patients with adult T-cell acute lymphoblastic leukemia (ALL) who can be successfully treated with chemotherapy alone and should not be subjected to the rigors of bone marrow transplants. The researchers found that these patients survived for at least three years after being treated with intensive chemotherapy. It was previously known that only slightly over half of the patients with this disease could be cured with chemotherapy. Adult ALL patients often undergo transplants in an effort to beat back the stubborn disease. Until now there was no way to identify those who have a more favorable outlook and shouldn’t undergo risky bone marrow transplantation.
Smoking may play a dual role in the development of a cancer of the lymph glands called follicular lymphoma — first causing it to develop and then transforming it into diffuse large cell lymphoma, an aggressive cancer generally associated with a poor prognosis.