Credit: Image: Courtesy of Shilatifard Lab, Stowers Institute for Medical Research.
Both the RNA polymerase II elongation factor ELL3 and RNA polymerase II localize to the nucleus of the mature mouse sperm. This finding raises the possibility that transcription factors could prime future gene expression by marking enhancers in embryonic stem cells or even as early as in the germ cell state. Mouse sperm were fixed, cryo-sectioned, and double stained with ELL3 (6 nm gold particles) and Pol II (12 nm gold particles) antibodies.