Use of phospholipase A2 for antigen retrieval in zebrafish whole-mount immunohistochemistry.

An advantage in zebrafish is that we can identify spatial and temporal patterns of protein expression using whole-mount immunohistochemistry. To allow primary antibodies to interact with their targets, most tissues must undergo some type of antigen retrieval. Many retrieval techniques have utilized protein-digesting enzymes to access antigens. Here we investigate the use of phospholipase A(2) (PLA(2)) as the sole enzyme for antigen retrieval as well as in combination with low concentrations of proteinase K. Concentrations of proteinase K used with PLA(2) are unable to expose the antigen when used as the sole enzyme. We demonstrate that PLA(2) is useful for both nuclear and cytoplasmic antigens but not for extracellular matrix components.