A protein known primarily for its role in the fight against cancer also contributes embryo implants in the womb, according to a study in mice. The discovery may explain why some women have difficulty becoming pregnant.
The p53 protein has been widely studied for its involvement in several anticancer mechanisms, such as the repair of DNA damage and initiate cell death to prevent tumor formation. (Mutations in p53 gene can lead to cancer.) The function of the p53 protein in normal conditions has remained a mystery, however. Last year, researchers led by reproductive endocrinologist Carolyn Coulam Rinehart Center for Reproductive Medicine in Evanston, Illinois, found an association between the women with certain variations of p53 and difficulty conceiving but the mechanism was unclear.
a team led by co-discoverer of p53 and Arnold Levine cancer biologist at the Institute for Advanced Study in Princeton, New Jersey, later noticed a link between p53 and fertility . The presence or absence of the gene seemed to have an effect if the female mice could become pregnant. In the new study, the team dug deeper, comparing high mouse to miss p53 with normal mice. While normal mice became pregnant after breeding and had litters of five to six puppies, only 63% of mice lacking p53 became pregnant and birthed litters of one or two small. In another strain lacking p53 , only 27% of designed and birthed puppies mouse.
Because the protein p53 fight against cancer by regulating certain genes, the researchers thought it probably had the same function in reproduction. An analysis of possible target genes identified suspect: the leukemia inhibitory factor ( LIF ) gene. LIF codes for a protein of the same name that helps embryos implant in the womb, and some nose leukemia cells.
Further experiments confirmed that p53 regulates LIF . female mice devoid of p53 gene had lower levels of LIF in their uterus, which is less than embryo implantation sites. Administration LIF these mice reversed their reproductive problems, improving their pregnancy rate at 100% and increase litter size, but had no effect on mice that carried the p53 gene, the researchers report in November 29 issue of Nature .
Coulam said the newfound role of p53 may explain infertility cases that involve a failure of the embryo to implant. The results also suggest a new role for drugs to treat cancer that targets p53 adds biologist Colin Stewart Development of Medical Biology Institute in Singapore. "Some of these drugs may be useful for helping women conceive by improving the function of p53 in the uterus. ... Others may be possible contraceptives by blocking the function of p53 in the uterus."
Related Sites
- p53 Overview
- More p53
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