Protein complexes that are involved in the regulation of transcription might be located near positions on the inner nuclear membrane. Certainly, at the very least, the architectural proteins (lamins) are involved in this, and the lamins which are present on the inner nuclear membrane may be as well.  Yesterday’s post revealed something I had not seen before which made me curious about the different (I saw at least three easily) “stringing” patterns of chromatin on the inner membrane, one very loose, one quite tightly together, and the third somewhere in the middle.  I searched about 100 other micrographs of type II cells from three species (ferret, dog, guinea pig) and found many examples of the tight configuration.  Accompanying the tight configuration is an apparent rigidity in that particular stretch of the inner nuclear membrane.  Searches online did not reveal much in the way of literature to explain it.  It seems reasonable to assume that the tightly spaced areas of DNA and other proteins is not going to be active. There were occasions when the tightly packed chromatin was close to a nuclear pore, but not always.  It also seemed as if there was a slightly greater electron density to the lamin area just beneath the tightly packed row than under the medium or loosely packed chromatin.

Red arrows point to loosely packed chromatin right at the inner nuclear membrane adjacent to the lamins, white arrows point to the tightly ordered chromatin, also right at the inner nuclear membrane adjacent to the lamins. Nuclear pores, pink, nucleus, blue, nucleolus purple,  lamellar bodies, yellow, cytoplasm, green.  There is also in this photograph a mitochondrion (the green color of the cytoplasm, in the lower left corner which is very close to the filaments of the nuclear pore….. something which is quite common and also something which I have not seen explained.