The nucleus is normally around 5-10 μm in diameter and is the largest organelle in the cell. A cell nucleus is the main characteristic that distinguishes eukaryotic from prokaryotic cells. The main functions of the nucleus include gene transcription, pre-mRNA splicing, DNA replication and the assembly of ribosomes. The nucleus is separated from the cytoplasm by the nuclear envelope, which comprises the inner nuclear membrane (INM) and the outer nuclear membrane (ONM). The outer nuclear membrane (ONM) is continuous with the endoplasmic reticulum and faces the cytoplasm. The nuclear lamina lies on the inner surface of the inner nuclear membrane where it provides structural support for the nucleus. The main proteins of the nuclear lamina are lamins belonging to the intermediate filament protein superfamily. Mammals express A and B type lamins. The B-type lamins include lamin B1, lamin B2 and lamin B3, whilst the main A type lamins are lamins A and C. Transport between the cytoplasm and the nucleus occurs through nuclear pores, which are specialized channels in the nuclear envelope. A nuclear pore is composed of a collection of proteins called nucleoporins (Nups) that together make up a nuclear pore complex. Such a complex exhibits a diameter of approximately 120 nm. DNA is packaged in the nucleus with the aid of histones (core histones: H2A, H2B, H3, H4 and linker histones: H1/H5) and is situated in the nucleoplasm along with sub-nuclear bodies. Numerous sub-nuclear bodies have been reported including nucleoli, splicing speckles, Cajal bodies (CB), gems and promyelocytic leukaemia (PML) bodies. Unlike cytoplasmic organelles, sub-nuclear bodies do not possess a delineating membrane separating them from the nucleoplasm. However, the expression of characteristic resident proteins and other factors in these distinct sub-nuclear bodies is indicative of their specific nuclear functions. The most prominent sub-nuclear body in the nucleus is the nucleolus and is involved in ribosome biogenesis. We offer a large range of nuclear markers including c-Myc antibodies, CENPA antibodies, Histone H3 antibodies, and SIRT1 antibodies, covering various antibody formats, host species, and conjugates. Nuclear marker antibodies can be used in various laboratory applications, including subcellular fractionation to identify specific nuclear fraction markers, thus verifying preparation purity, and to probe other subcellular fractions for nuclear contamination.