Zhao ZW, Roy R, Gebhardt JC, Suter DM, Chapman AR, Xie XS.

Proc Natl Acad Sci U S A. 2014 Jan 14;111(2):681-6. doi: 10.1073/pnas.1318496111.

Spatial organization of RNA polymerase II inside a mammalian cell nucleus revealed by reflected light-sheet superresolution microscopy.

80,000 type II polymerase per nuclei, solitary in more than 70 % of the cases. Shortly after fixation on coverslips, nuclei flatten.