Serine proteases in the spiny lobster olfactory organ: their functional expression along a developmental axis, and the contribution of a CUB-serine protease.

Several serine proteases and protease inhibitors have been identified in the crustacean olfactory organ, which is comprised of the lateral flagellum of the antennule and its aesthetascs sensilla that house olfactory receptor neurons and their supporting cells. The function of these proteases in the olfactory organ is unknown, but may include a role in perireception (e.g., odor activation or inactivation) or in the development or survival of olfactory receptor neurons. To examine directly the function of proteases in the olfactory organ of the Caribbean spiny lobster Panulirus argus, we used different tissue fractions from the lateral flagellum in an enzyme activity assay with a variety of protease substrates and inhibitors. Trypsin-like serine protease activity occurs throughout the lateral flagellum but is enriched in the cell membranes from aesthetascs. Cysteine- and metalloprotease activities also occur in olfactory tissue, but are more abundant in tissue fractions other than aesthetascs. To assess the contribution of one of the olfactory serine proteases--CUB-serine protease (Csp)--Csp was immunoprecipitated using an antibody; results with the remaining fraction suggest that Csp accounts for at least 40% of the total serine protease activity in the olfactory organ. The amount of total serine protease activity follows a developmental axis in the lateral flagellum. Total protease activity is lowest in the proximal zone, which lacks aesthetascs, and the proliferation zone, where olfactory receptor neurons and associated cells are born, and highest in aesthetascs of the distally-located senescence zone, which has the oldest olfactory tissue.

Expression of ADAMTS1 during murine development.

ADAMTS1/METH1 belongs to the ADAMTS (a disintegrin and metalloprotease with thrombospondin repeats) family of proteins that currently comprises 18 members. Targeted inactivation of the ADAMTS1 gene results in morphological defects in the kidney, adrenal gland, and adipose tissue in addition to growth retardation and infertility in females. To gain further insight on the biology of ADAMTS1, we examined its expression pattern in the developing mouse from embryonic day 10 (E10) to E18. Expression analysis by RNase protection assays revealed detectable levels of ADAMTS1 transcripts in E10-E18 yolk sac, placenta, brain, heart, lung, limb bud, liver, spleen, and kidney, with much lower levels in the adult. Using in situ hybridization, we have localized ADAMTS1 transcripts predominantly to the epithelium of the developing lung, pancreas, kidney and to a subset of neurons in a temporally restricted manner. Expression was also detected in the tunica media of the aorta, pulmonary, and hepatic vessels.