Week in Review: January 26–30

Two TSPO structures; optogenetics used to define neurons associated with thirst and overeating; transposons and the evolution of pregnancy

Jan 30, 2015
Tracy Vence

Function conundrum

FEI LITwo crystal structures for translocator protein (TSPO)—from the bacteria Bacillus cereus and Rhodobacter sphaeroides—are the latest pieces in the puzzle that is determining the functions of this integral mitochondrial membrane protein. The structures, published in Science this week (January 29), are a match, but they differ from a published murine TSPO.

“Membrane proteins are very difficult to work on . . . so when you have two independent groups actually coming up with seemingly identical or very similar structures, it’s very gratifying,” said structural biologist Chris Tate of the Medical Research Council’s Laboratory of Molecular Biology in Cambridge, UK, who was not involved in the studies.

“This protein is 5 billion years old, so it has been evolving over all that time and has adapted to the various needs of the tissues, cells, and species. . . . It’s not surprising that it may really have diverse roles,” Vasillios Papadopoulos, a professor of medicine at McGill University in Montreal who was not involved in the work, told The Scientist.

Defining overeating neurons

MIT, EDWARD NIEH, KARA PREBREY, AND KAY TYEUsing a modified optogenetics approaches, two groups have zeroed in on neurons in the mouse lateral hypothalamus (LH) that are linked to eating in excess. Their studies were published in Cell this week (January 29).

“These are big papers that start to define the complexity and heterogeneity of [the hypothalamus] and the specific sets of neurons that can produce dramatic behavioral results,” said Ralph DiLeone, a neurobiologist at Yale University who was not involved in the work.

“We’ve had the electrical stimulation findings for more than 30 years now, but we didn’t know [which neurons] we were stimulating and whether the feeding-related neurons are from the LH or are just passing through until optogenetics techniques became available,” said Roy Wise, a neuroscientist at the National Institute on Drug Abuse who was not involved in the work.

Defining thirst neurons

WIKIMEDIA, TIIA MONTOAgain using optogenetics, another group has defined in greater detail than ever before hypothalamic neurons involved in mouse drinking. The work was published in Nature this week (January 26).

“It’s a very elegant study using optogenetics to identify separate cell populations that clearly act in opposite ways on thirst,” said Joseph Verbalis of Georgetown University who was not involved in the study.
 

Evolution of pregnancy

FLICKR, TATIANA VDBTransposons may have played an influential role in the evolution of pregnancy, researchers reported in Cell Reports this week (January 30). Sequencing RNA from across the animal kingdom and comparing uterine gene expression in several mammal species, scientists from the University of Chicago homed in on transposable elements that appear to have altered the expression of pregnancy-related genes over time.

This work “adds to the evidence that transposable elements are major forces of evolution and rapid evolution, particularly in the reproductive organs,” said Julie Baker, a geneticist at Stanford University in Palo Alto, California, who was not involved in the study. “I think we’re going to see a lot more attention paid to the evolution of transposable elements and their function.”

Other news in life science:

Interferon Discoverer Dies
Jean Lindemann, the virologist who helped figure out that interferons were responsible for anti-viral responses, has passed away at age 90.

Ebola Epidemic on the Wane?
The number of reported cases is dropping in West Africa, World Health Organization officials report.

Laser Inventor Dies
Charles Townes, Nobel Prize-winning physicist, has passed away at age 99.

Drug Stimulates Brown Fat
A small study finds that an approved medication increases metabolic rate and the activity of thermogenic brown fat in men.

Myriad Settles Suit
The Utah-based firm has settled its lawsuit claiming patent infringement against Pathway Genomics.