Science  16 Sep 2011:
Vol. 333, Issue 6049, pp. 1558

You are currently viewing the .

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

  1. Glowing Kittens Fight Feline AIDS


    Scientists have genetically modified cats by infecting their eggs with a virus containing a foreign gene—the first time this method has worked in a carnivore. The advance could make the cat a valuable new genetic model—and potentially protect it from the feline immunodeficiency virus (FIV).

    Human immunodeficiency virus (HIV) and FIV, both lentiviruses, are different enough that cats can't catch HIV and people can't get FIV. Previous studies have suggested that a protein called TRIMCyp, which cats lack, keeps humans and monkeys from being infected with FIV. To see if giving cats the TRIMCyp gene would make them immune to FIV, Eric Poeschla, a molecular virologist at the Mayo Clinic in Rochester, Minnesota, made a lentivirus containing the TRIMCyp gene as well as a gene that encodes for a fluorescent protein, which would let him see which cells contained the new genes. After allowing the virus to infect cat egg cells, the team fertilized the eggs and injected them into the fallopian tubes of 22 female cats.

    Ultimately, the technique worked, producing three kittens, the team reported online 11 September in Nature Methods. Furthermore, when the researchers tried to infect blood cells from the genetically modified kittens with FIV, the virus didn't replicate well.

  2. Questioning Folic Acid's Fetal Benefit

    Since 1998, the U.S. has fortified grains with folic acid because many pregnant women naturally consume too little of the vitamin, increasing the odds their babies will have neural tube defects such as spina bifida. Now a provocative animal study in the 15 September issue of Human Molecular Genetics suggests supplementing diets with folic acid can itself sometimes promote birth defects.

    Lee Niswander, a Howard Hughes Medical Institute investigator at the University of Colorado, Denver, heads a team that gave long-term folic-acid supplemented diets to five mutant mice strains prone to developing neural tube defects. In three of the strains, the extra folic acid increased the number of neural tube defects, decreased embryo survival, or did both. Niswander isn't calling for an end to folic acid supplementation, but urges study into whether some women would be better off without a boost. “It would really be throwing the baby out with the bath water to say that because of this one mouse study we are going to question the food fortification,” cautions Roy Pitkin, a clinician who chaired an Institute of Medicine panel that reviewed folic acid's health effects in 2000.