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Archive - Mar 4, 2016

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Scientists Obtain Deeper Insight into Function of BRCA1 Gene (Angelie Jolie Gene)

Scientists from the Cancer Therapy & Research Center (CTRC) in San Antonio today (March 4, 2016) published work that provides deeper insight into how the so-called “Angelina Jolie” gene, BRCA1, functions in normal breast tissue and how its loss results in breast cancer. The CTRC -- a National Cancer Institute-designated Cancer Center -- is part of the University of Texas (UT) Medicine San Antonio, the clinical practice of the School of Medicine at The University of Texas Health Science Center at San Antonio. BRCA1 is known to suppress cancer by repairing breaks in DNA, the molecule that contains the genetic blueprint of each cell. This DNA damage occurs with aging and environmental insults. In the new study, published online Nature Communications, CTRC researchers found that BRCA1 also serves as a limiter or governor on a gene called COBRA1 that regulates breast cell growth. The new open-access article is titled “Genetic suppression reveals DNA repair-independent antagonism between BRCA1 and COBRA1 in mammary gland development.” "We now have solid and compelling evidence that BRCA1 in breast tissue is doing something independent of DNA repair," said study lead author Rong Li, Ph.D., Professor of Molecular Medicine at the Health Science Center. "We still think DNA repair is important for BRCA1 to suppress tumor development, but we just don't think it's the whole story." Because DNA repair is needed in every cell of the body, scientists, including Dr. Li, have puzzled over why loss of BRCA1 function predisposes women to only breast and ovarian cancers. Also, diminished BRCA1 activity doesn't affect men significantly, as it does women.

Lifespan in Nematode Hermaphrodites

Pristionchus nematodes come in two varieties: Most species consist of typical males and females, but in several species the females have evolved the ability to produce and use their own sperm for reproduction. Scientists from the Max Planck Institute of Developmental Biology in Tübingen, Germany, discovered that these so called “hermaphrodites” have shorter lifespans, with normal females frequently living over twice as long as closely related hermaphrodites. The article was published online on February 18, 2016 in The American Naturalist and is titled “Mating System Transitions Drive Life Span Evolution in Pristionchus Nematodes.” The ways that males and females interact affects many biological processes, including the evolution of important traits like lifespan and the rate of aging. While the male-female mating system is found in most vertebrates, and all mammals--many animal species employ alternative arrangements. Ralf Sommer, Ph.D, and Cameron Weadick, Ph,D., from the Max Planck Institute of Developmental Biology are doing research on the evolutionary consequences of such differences. They wanted to find out if self-fertilizing hermaphrodite nematodes would evolve to live longer, healthier lives; or if they would evolve shorter life cycles, characterized by quick bursts of reproduction followed by senescent decay. By comparing species that utilize different mating systems, it's possible to see how much of a role sexual interactions play in shaping life-history evolution. The researchers measured adult lifespan in females and hermaphrodites from eleven different Pristionchus nematode (roundworm) species. They discovered that hermaphrodites, which fertilize their own eggs with their own sperm, live significantly shorter than their female relatives.