- Interleukin 2 receptor gamma chain (gamma(c)) knockout mice show less regularity in estrous cycle but achieve normal pregnancy without fetal compromise. Miyazaki, S., Tanebe, K., Sakai, M., Michimata, T., Tsuda, H., Fujimura, M., Nakamura, M., Kiso, Y., Saito, S. Am. J. Reprod. Immunol. (2002)