Two McMaster University studies, to be published in the Journal of Virology, show that sex hormones have a profound effect on susceptibility of female mice to the herpes simplex virus, type 2 (HSV-2 ), one of the most common sexually transmitted diseases.

Charu Kaushic, assistant professor and supervisor of the studies, says the implication of this work is quite significant. "The research clearly shows, and reaffirms previous research, that in female mice, sex hormones have a profound effect on susceptibility to sexually transmitted infections as well as on the body's defense mechanisms against them."

Retroviruses are expert manipulators when it comes to co-opting their host's cellular resources. A great deal of human complexity stems from the vast repertoire of proteins and mechanisms dedicated to the business of regulating gene expression, and retroviruses like HIV have evolved myriad ways of redirecting that machinery to their own benefit.

Humans and other eukaryotes have three types of RNA polymerases, each charged with transcribing different types of genetic elements. RNA polymerase II transcribes protein-coding genes. RNA polymerases join with so-called general transcription factors to form a pre-initiation complex (PIC) on the gene's promoter, where it binds to region rich in thymine (T) and adenine (A) named the TATA box. The first transcription factor to associate with the TATA box is called TFIID, a large protein complex containing a protein that binds the TATA box (aptly named the TATA-box-binding protein, or TBP) and several cofactors called TBP-associated factors (TAFs). PIC assembly sometimes also requires activator proteins, which can enhance transcriptional activity by supporting proper elongation of nascent transcripts.

Tat, an activator encoded in the HIV genome, is required for HIV gene activation and viral replication. It affects these processes, the current model holds, by stimulating transcript elongation and increasing RNA polymerase's processing efficiency. In a new study, Tamal Raha, Grace Cheng, and Michael Green work with human cell lines and find evidence that Tat can also stimulate PIC assembly.

Nearly 40 years after an historic anthropology expedition to Ethiopia's Lake Turkana basin, researchers have uncovered evidence suggesting human bones found at that time are roughly 195,000 years old. The researchers believe the findings may bolster the “Out-of-Africa” hypothesis that suggests we all trace to an ancient line that first evolved in Africa and then displaced other hominids as recently as 50,000 years ago.

Ian McDougall of Australian National University (ANU), Frank Brown of the University of Utah and John Fleagle of Stony Brook University, report their findings in the Feb. 17 issue of the journal Nature.

The fossils, from near the town of Kibish, are far more ancient than researchers originally suspected and nearly 40,000 years older than skulls from Herto, Ethiopia, the previous record holders.

Biochemist Glenn King is searching for an alternative to chemical pesticides. King's research on insect-specific neurotoxins focuses on one the world's most efficient insect predators -- spiders. The Blue Mountains funnel-web spider (Hadronyche versuta) -- a large Australian spider with a bite that is deadly to humans and insects -- is an ideal source of venom for King's research. The spider "cooperates" by rearing up in a fighting stance when provoked, making it relatively easy for researchers to aspirate venom directly from its fangs. Since Australian funnel-web spiders can live for more than five years in captivity, a small group of these spiders yields plenty of toxins for King's chemical analysis.

Funnel-web spider venom is a complex brew of more than 100 chemical compounds, most of which are toxic to insects, but not vertebrates. King is studying the molecular structures of the toxins that selectively target the nervous systems of insects to understand the toxins' mechanism of action at the cellular level. Because these toxins do not affect the mammalian nervous system, it may be possible to use them to create environmentally friendly insecticides.

Utah State University researchers recently discovered a new bacteria that is a natural cleanser for contaminated soil. The bacteria, now being used around the world, is an inexpensive and highly effective solution to pollution.

“This project shows mother nature’s capability to be a master engineer,” said Ron Sims, biological and irrigation engineering department head. “Past disposal practices and accidental spills have put these carcinogens in our environment, and nature has figured out a way to cleanse herself. We want to be able to understand it better through genomic analysis.”

Genomes throughout the animal kingdom and beyond are characterized by extensive segments that are inactive, lengthy stretches of DNA containing multiple genes that are closed to gene transcription. Scientists believe one reason for this broad gene silencing is the vital need for genomic stability, for protection against unwanted recombinations of genetic material or other disruptions of the genome's integrity.

Genomic instability, particularly in the regions at the ends of the chromosomes known as telomeres, has been linked to aging in humans and an elevated risk for aging-related diseases, the most prominent of which is cancer. For this reason, insights into the mechanisms of gene silencing could provide important guideposts for new approaches to retarding aging or treating cancer.

Now, an investigation led by researchers at The Wistar Institute has shown that an enzyme known as Ubp10 plays a vital role in protecting the telomeric regions of the genome from potential destabilizing molecular events. The enzyme helps to keep the genome structurally closed, unavailable for transcription and possibly protected from dangerous genetic recombinations with other regions of the genome. A report on the research, which was conducted in yeast, appears in the February 18 issue of Molecular Cell.