This MAb is an excellent marker for all nuclei in cells in tissues. It is a part of a new panel of reagents, which recognizes subcellular organelles or compartments of cells. These markers may be useful in identification of these organelles in cells, tissues, and biochemical preparations. This MAb recognizes an antigen associated with the nuclei in all cells. It can be used to stain the nuclei in cell or tissue preparations and can be used as a nuclear marker in subcellular fractions. It produces a speckled pattern in normal and malignant cells and may be used to stain the nuclei of cells in fixed or frozen tissue sections. It can also be used with paraformaldehyde fixed frozen tissue or cell preparations.