Sjogren's syndrome, an autoimmune disease affecting the salivary and lacrimal glands, causes gland degeneration through inflammatory lesions made of lymphocytes. This causes symptoms of dry eyes and mouth. MRL/lpr mice have been used as models of the lymphocytic infiltration characteristic of Sjogren's syndrome, and several immunohistochemical and genetic analyses have been performed on MRL/lpr lacrimal glands.
β-Actin (ACTB) is a ubiquitously expressed cytoskeletal protein. Involved in cell movement and structure, it is usually expressed at constant levels within the cell. We have successfully cloned and sequenced ACTB cDNA from little skate (Leucoraja erinacea) from the 5' untranslated region through the poly-adenylated tail. The deduced protein was 374 amino acids in length, with a 99.7% identity to the human ortholog of ACTB. ACTB is highly conserved among vertebrates and is used as a protein loading control in Western blots and other experiments in which heterogeneous samples are used. In recent years, ACTB has been used as a reference gene in quantitative real-time polymerase chain reaction (qPCR) studies where it is used as a control for amplification variations between samples.