Localization and expression of phospholipases A₂ in Trimeresurus flavoviridis (habu snake) venom gland

The localization and expression profiles of phospholipases A₂ (PLA₂s) in Trimeresurus flavoviridis venom gland were studied by means of in situ hybridization and immunohistochemical techniques. Venom gland cells are tightly arrayed in a single layer along the inlet-like lumens in which venom proteins are stored. mRNAs for PLA₂s were detected at the high level in cytoplasm. Using the immunohistochemical technique with polyclonal antiAsp-49-PLA₂ antibody, Asp-49-PLA₂ and, possibly, its isozymes were detected in intracellular granules and in venom lumens. The intracellular granules containing PLA₂ proteins appear to be transferred from the nucleus towards the outer membrane facing the lumen, and then to be secreted.