Genetics & Molecular Biology
Cells keep a close watch over the transcriptome – the totality of all parts of the genome that are expressed in any given cell at any given time. Researchers at the Salk Institute for Biological Studies and the University of Missouri-Kansas City teamed up to peel back another layer of transcriptional regulation and gain new insight into how genomes work.
Converting the “genetic blueprint” into molecular building blocks requires two basic processes: transcription, which copies the information from DNA into RNA transcripts and takes place in the cell’s nucleus, and translation, where the RNA serves as a template to manufacture proteins outside the nucleus.
Genome rearrangements, resulting in variations in the numbers of copies of genes, occur when the cellular process that copies DNA during cell division stalls and then switches to a different genetic “template,” said researchers at Baylor College of Medicine in Houston in a report that appears today in the journal Cell.
The new mechanism is called replication. “Fork Stalling and Template Switching,” said Dr. James R. Lupski, Cullen professor of molecular and human genetics and vice chair of the department at BCM. It not only represents a new way in which the genome generates DNA copy number variation, but it also demonstrates that copy number variation can occur at a different time point in the life of a cell. DNA replication takes place as the cell is dividing and becoming two.
According to the Centers for Disease Control and Prevention, close to one-third of the population in the United States is obese and another third is overweight.
Excessive weight gain is elicited by alterations in energy balance, the finely modulated equilibrium between caloric intake and expenditure. But what are the factors that determine how much food is consumed?
Part of the mystery is unfolding in the laboratory of Maribel Rios, PhD, at the Sackler School of Graduate Biomedical Sciences at Tufts University School of Medicine in Boston. Through their work, Rios and colleagues have demonstrated for the first time that a protein called brain-derived neurotrophic factor (BDNF) is critical in mediating satiety in adult mice.
Viticulture, the growing of grapes Vitis vinifera, chiefly to make wine, is an ancient form of agriculture, dating as far back as the Neolithic and Early Bronze Ages.
We have a detailed understanding of how nurture affects the qualities of a grape harvest leading to the concept of terroir (the range of local influences that carry over into a wine). The nature of the grapes themselves has been less well understood but the publication of a high quality draft genome sequence of a Pinot Noir grape by an Italian-based multinational consortium may change that.
When humans began to migrate out of Africa about 100,000 years ago, their skin color gradually changed to adapt to their new environments. And when the last Ice Age ended about 10,000 years ago, marine ancestors of ocean-dwelling stickleback fish experienced dramatic changes in skin coloring as they colonized newly formed lakes and streams.
New research shows that despite the vast evolutionary gulf between humans and the three-spined stickleback fish, the two species have adopted a common genetic strategy to acquire the skin pigmentation that would help each species thrive in their new environments.
Surrounding the small islands of genes within the human genome is a vast sea of non-coding DNA. While most of this DNA is junk, some of it is used to help genes turn on and off.
Hopkins researchers write in Genome Research that they have now found that regulatory DNA, which contributes to inherited diseases like Parkinson’s or mental disorders, may be more abundant than we realized.
By conducting an exhaustive analysis of the DNA sequence around a gene required for neuronal development, Andrew McCallion, Ph.D., an assistant professor in the McKusick-Nathans Institute of Genetic Medicine, and his team found that current computer programs that scan the genome looking for regulatory DNA can miss more than 60 percent of these important DNA regions.
Boosting an exercise-related gene in the brain works as a powerful anti-depressant in mice—a finding that could lead to a new anti-depressant drug target, according to a Yale School of Medicine report in Nature Medicine.
“The VGF exercise-related gene and target for drug development could be even better than chemical antidepressants because it is already present in the brain,” said Ronald Duman, professor of psychiatry and senior author of the study.
Depression affects 16 percent of the population in the United States, at a related cost of $83 billion each year. Currently available anti-depressants help 65 percent of patients and require weeks to months before the patients experience relief.
Embryonic stem cells (ESC) can both self-renew or differentiate into the many cells of the organism and it is crucial to understand the mechanism behind this capability if we want to use them in clinic.
Developmental regulator genes are responsible for the activation of many ESC differentiation-pathways and, as such, they are a fundamental key to understand them. And now, research about to be published in Nature Cell Biology, reveals that these genes -always believed to be inactive in ESC before differentiation start - when apparently silent (non-active) are in fact poised, already on the first steps of gene activation only unable to go further due to the presence of repressor molecules.
A variant of the gene CDC2 could possibly be used as a risk marker for Alzheimer’s disease. The gene variant is considerably more common among Alzheimer’s patients. This is shown in a dissertation from the Sahlgrenska Academy at Göteborg University in Sweden.
Alzheimer’s disease has several different causes. Since many patients have a close relative who also developed the disease, heredity is believed to be one of the most important factors.
“There is a previously identified Alzheimer’s gene that indicates an elevated risk of developing the disease, but we want to find more genes with a strong connection to Alzheimer’s.
Headlines last week reported that researchers successfully produced stem cells from cloned monkey embryos
. Using a process that has become almost routine with mice, scientists can now make make primate embryonic stem cells that are genetically identical to a given DNA donor. Once we learn to do this in humans, the possibility of stem cell based treatments for heart disease, neurodegeneration, and more will be closer to reality. But in the US and elsewhere, can we develop the political will to let this research move forward?