Genes & Cells

Turning HIV away
A newly identified gatekeeper protein in some white blood cells may keep HIV out. The protein, called SAMHD1, blocks the AIDS virus from insinuating its DNA into common white blood cells called dendritic cells, a team of French researchers reports online May 25 in Nature. Without these functioning security guards, the immune cells become saddled with 13 times more viral DNA. That could explain why dendritic cells frequently repel HIV invasions while other white blood cells fall prey to the pathogen. Such gatekeepers could inspire anti-HIV vaccines, the group says. —Daniel Strain

Gene therapy for dogs
Gene therapy can reverse a bleeding disorder in dogs. Researchers studied a line of Great Pyrenees dogs with a genetic mutation that prevents their blood platelets from clotting. These dogs experience the same symptoms as people with inherited platelet diseases. Researchers led by David Wilcox of the Medical College of Wisconsin in Milwaukee engineered blood stem cells to carry a gene required for healthy platelets and injected the cells into four dogs. After treatment, three dogs improved and remained healthy years later, and one dog died. The results demonstrate the feasibility of exploring gene therapy as a way to treat bleeding disorders in humans, the researchers suggest in paper published online May 23 in the Proceedings of the National Academy of Sciences. —Laura Sanders

Express neurons
The prospect of making replacement brain cells from a patient’s skin just took one step closer to reality. Zhiping Pang of Stanford University and his colleagues have now converted foreskin cells directly into neurons. The group had previously shown that mouse skin cells could be turned into neurons with the addition of three genes (SN: 2/27/10, p. 5). In a new study published online May 26 in Nature, Pang and his colleagues show that human cells need a little extra help from a gene called NeuroD1 to make the skin-cell-to-brain-cell transition. The current method produces mainly one type of neuron. The researchers hope to learn how to create the hundreds of types of neurons that make up the brain, spinal cord, and other nerves in the body. —Tina Hesman Saey