Circadian rhythms go both ways: in and from retina

Removal of Bmal1 accelerates the deterioration of vision that comes with Read more

Genomics plus human intelligence

The power of gene sequencing to solve puzzles when combined with human Read more

'Master key' microRNA has links to both ASD and schizophrenia

Recent studies of complex brain disorders such as schizophrenia and autism spectrum disorder (ASD) have identified a few "master keys," risk genes that sit at the center of a network of genes important for brain function. Researchers at Emory and the Chinese Academy of Sciences have created mice partially lacking one of those master keys, called MIR-137, and have used them to identify an angle on potential treatments for ASD. The results were published this Read more

long term potentiation

BAI1: a very multifunctional protein

Everything is connected, especially in the brain. A protein called BAI1 involved in limiting the growth of brain tumors is also critical for spatial learning and memory, researchers have discovered.

Mice missing BAI1 have trouble learning and remembering where they have been. Because of the loss of BAI1, their neurons have changes in how they respond to electrical stimulation, and subtle alterations in parts of the cell needed for information processing.

The findings may have implications for developing treatments for neurological diseases, because BAI1 is part of a protein regulatory network neuroscientists think is connected with autism spectrum disorders.

The results were published online March 9 in Journal of Clinical Investigation.

Erwin Van Meir, PhD, and his colleagues at Winship Cancer Institute of Emory University have been studying BAI1 (brain-specific angiogenesis inhibitor 1) for several years. Part of the BAI1 protein can stop the growth of new blood vessels, which growing cancers need. Normally highly active in the brain, the BAI1 gene is lost or silenced in brain tumors, suggesting that it acts as a tumor suppressor.

The researchers were surprised to find that the brains of mice lacking the BAI1 gene looked normal anatomically. They didn’t develop tumors any faster than normal, and they didn’t have any alterations in their blood vessels, which the researchers had anticipated based on BAI1’s role in regulating blood vessel growth. What they did have was problems with spatial memory.

Read more

Posted on by Quinn Eastman in Cancer, Neuro Leave a comment

Smart mice, clever names and some context

This week a variety of media outlets and science-oriented Web sites had fun with research at Emory — published recently in PNAS — investigating a gene that appears to limit some forms of learning and memory.

Mice with a disabled RGS14 gene remembered objects in their cages more easily and learned to navigate water mazes better, pharmacologist John Hepler and his colleagues found. Since the presence of a functional RGS14 gene holds mice back mentally, Hepler and his colleagues have been jokingly calling it “the Homer Simpson gene.”

This description struck a chord; the Atlantic magazine even embellished the story with a video showing the “D’oh”-ey cartoon character evolving from a single cell into a human couch potato.

It’s important to recognize that smart mice are not so surprising to scientists anymore. Back in 1999, scientists at Princeton announced the creation of “Doogie Howser” mice (named after a precocious doctor from another TV series). These critters performed better than normal lab mice in some of the same tests that Hepler’s team used to evaluate the RGS14-deleted mice.

One important difference: the Doogie mice had all their normal genes, and were overproducing a NMDA receptor gene involved in helping neurons communicate. Still, as a helpful 2009 round-up in Nature Reviews Neuroscience explains, scientists have found several single-gene knock-out mice that do better on tests of learning and memory. Many of these genetic alterations affect the process of long term potentiation, a process where neurons that get stimulated at the same time have the connections between them grow stronger.

RGS14 is turned on primarily in the CA2 region of the hippocampus

What makes the RGS14 gene an intriguing case is that it’s primarily turned on in the enigmatic CA2 region of the hippocampus. The CA2 region is normally relatively resistant to long-term potentiation and is also more hardy in situations of stroke or seizure.

Hepler observes that the vasopressin receptor 1b gene is also turned on predominantly in the CA2 region, and seems to be involved in aggression and social memory. He and his colleagues are planning to examine whether the RGS14-disabled mice have altered capabilities in those areas. Conveniently, Larry Young’s laboratory at Yerkes National Primate Research Center has been investigating the functions of vasopressin receptors in voles.

One last note: scientists in Spain have reported in Science that they can generate a variety of smart mice by putting the RGS14 gene on overdrive in a part of the brain where it’s not usually turned on. So whatever precise function RGS14 has, it doesn’t always dumb things down.

Posted on by Quinn Eastman in Neuro 1 Comment