Genetics & Molecular Biology

Gleaning from the natural process of X chromosome inactivation, scientists recently discovered a way to “turn off” the extra copy of chromosome 21 in Down syndrome, a strategy that might one day cure this disorder. The 23 pairs of chromosomes  in the human genome is the product of nature’s elusive calculations to caliber the precise levels of gene expression in the cell- a calibration crucial for the normal function of human tissues and organs. The presence of one too many chromosomes, such as the extra chromosome 21 in Down syndrome, can have serious consequences. Among the most…

Scientists have revealed the genetic secrets of how a small bird, Parus humilis  (ground tit) can survive in one of the most hostile environments on earth - the Tibetan plateau, the largest high-altitude land mass in the world. The study found molecular signatures in the ground tit genome which reveal how it copes with the extreme living conditions of this habitat, said co-authors Professor David Lambert and Dr. Sankar Subramanian from Griffith University.   Unlike its tree-dwelling relatives, the drab-colored little songbird lives exclusively above the tree line at 3,300 to 5…

In 1953, the lightbulb went on for Watson and Crick, who first published the famous double helix 3-D structure of DNA. Structural biology soon became a hot field. Using high intensity X-ray beams, NMR, and other hardware advances, coupled with exponential advances in software algorithims, molecular biologists can now easily solve the 3-D structure of many proteins (but not all, at least yet) with the resolution of single digit angstroms. RNA is now entering the fray as the final frontier. After all, it is only the key link between DNA and proteins. It is much more diverse and complicated…

Every cell in an organism's body has the same copy of DNA, though different cells do different things so some function as brain cells, while others form muscle tissue. How can the same DNA make different things happen? Science is a step closer to answers and maybe even to putting in a piece of the autism puzzle. Scientists know that much of what a gene does and produces is regulated after it is turned on. A gene first produces an RNA molecule, to which tiny RNA binding proteins (RBPs) bind and control its fate. For example, some of these proteins cut out parts of the RNA molecule so that it…

Next-generation hydrogels can form synthetic scaffolds to support the formation of replacement tissues and organs in the emerging area of regenerative medicine. Embedding peptides into the hydrogels stimulates the growth of essential microvascular networks to ensure a good blood supply.  A new paper describes the technology in which hydrogels functionalized with laminin-derived peptides were transplanted in a mouse cornea and were shown to support cell growth and blood vessel formation. Saniya Ali and coauthors from Rice University and Baylor College of Medicine, Houston, TX, and Duke…

Scientists recently discovered surprising evidence that more brown fat (as a result of cold treatment) could increase a person’s risk of getting a stroke or a heart attack. The finding could explain why more people die of cardiovascular diseases during the winter months. Brown fat consists of fat cells with a high metabolic rate, and the high metabolism in these cells can help burn fat and generate heat. These are unlike white fat cells, which have a much lower metabolic rate, and function mainly to store fat, contributing to obesity. Interestingly, white fat cells can acquire the properties…

The transcription factor Nanog plays a critical role in the self-renewal of embryonic stem cells and is expressed in a manner similar to other pluripotency markers, according to a new paper This finding contradicts the field's presumptions about this important gene and its role in the differentiation of embryonic stem cells.  A large body of research has reported that Nanog is allelically regulated—that is, only one copy of the gene is expressed at any given time—and fluctuations in its expression are responsible for the differences seen in individual embryonic stem (ES) cells'…

‘Jumping genes’ found in most living organisms don’t ultimately kill off their hosts, which is a long-standing scientific mystery.  A new paper reveals how the movement and duplication of transposons is regulated, which prevents a genomic meltdown and instead enables transposons to live in harmony with their hosts - including humans.  Transposons were discovered in the 1940s by Barbara McClintock, who was rewarded in 1983 with the Nobel Prize for Physiology or Medicine. Ancient relics of these ‘jumping genes’, as they are sometimes called, make up 50 per cent of the DNA in humans.…

Two proteins involved in oral taste detection, TAS1R3 and GNAT3, also play a crucial role in sperm development, according to a new paper. While breeding mice for taste-related studies, the researchers discovered that they were unable to produce offspring that were simultaneously missing two taste-signaling proteins: TAS1R3, a component of both the sweet and umami (amino acid) taste receptors; and GNAT3, a molecule needed to convert the oral taste receptor signal into a nerve cell response.  Breeding experiments determined that fertility was affected only in males. Both taste proteins had…

The liver receptor homolog-1 (Lrh-1) molecule first shown to function in the liver plays a crucial role in pregnancy in mice and has a key role in the human menstrual cycle, according to researchers at the University of Montreal.  Mice that were genetically engineered not to produce Lrh-1 were unable to create the uterine conditions necessary for establishing and sustaining pregnancy, resulting in the formation of defective placentas. The researchers then showed that Lhr-1 was present in the human uterus and the essential processes related to the success of early gestation.  "…