Nuclear loading controls are reference proteins used to ensure that equal amounts of total protein are loaded onto a gel during Western blot analysis, independent of sample size or target protein concentration. Using loading controls, researchers can normalize the concentration of their target protein to the stably expressed reference. This is important for comparing the amount of a target protein across different experimental samples, ensuring that apparent variations in the target protein’s concentration represent true biological differences rather than technical differences in sample loading. In addition, loading controls can be used to determine if the transfer process from gel to membrane was successful and proteins were transferred equally across the membrane. It is important to choose an appropriate loading control for the target protein being analyzed. Ideally, loading controls should exhibit high, constitutive expression in the cell type and subcellular compartment being studied and be present in similar amounts in all samples. It should be confirmed that the expression of the loading control isn’t affected by the conditions of a particular experiment, such as the introduction of mutations or chemical treatments. Commonly used nuclear loading controls include proteins found at the nuclear periphery, such as lamin B1, and DNA-binding proteins, including histone H3, HDAC1, PCNA, TBP, and YY1. These proteins exhibit relatively ubiquitous expression in mammalian cells and relatively constant levels in the nucleus. Lamin B1: An intermediate filament protein found in the nuclear lamina. As lamin B1 is associated with chromatin and the fibrous meshwork of the lamina, adequate solubilization typically requires sonication and DNA cleavage during extraction. Histone H3: One of the major histones involved in the packaging of DNA. PCNA: Proliferating cell nuclear antigen (PCNA) is a cofactor of DNA polymerase delta and is essential for DNA replication. TBP: TATA-binding protein (TBP) is a transcription factor that binds to the TATA box DNA sequence found in the promoter region of genes. YY1: A transcription factor that alternatively activates or represses transcription in a context-dependent manner. We offer a large range of nuclear loading control antibodies including HDAC1 antibodies, Histone H3 antibodies, Lamin B1 antibodies, PCNA antibodies, and TBP antibodies, covering various host species, antibody types, and formulations. You can also explore our other loading control antibodies by sample type.