title: Immunolocalization of venom metalloproteases in venom glands of adult and of newborn snakes of Bothrops jararaca.
abstract: Using immunoelectronmicroscopy we analyzed qualitative and quantitatively the intracellular distribution of bothropasin, hemorrhagic factor 2 (HF2) and hemorrhagic factor 3 (HF3) in the venom secretory cells from adult snakes in the active (7 days after venom extraction) and in the resting (without venom extraction for 40 days) stages of protein synthesis. Glands from the newborn Bothrops jararaca were also studied. The results lead to the conclusion that all the secretory cells and the secretory pathway in the cells are qualitatively alike in regard to their content of the three metalloproteases. Secretory cells from the resting glands, unlike the active ones and the newborn glands, did not present immunolabeling in the narrow intracisternal spaces of the rough endoplasmic reticulum (RER). The label intensity for bothropasin was greater than that for the other proteins in the adults. HF3 and HF2 labeling densities in the newborn were higher than in the adults and HF3 labeling was not different from that of bothropasin. Co-localization of the three metalloproteases was detected in the RER cisternae of the active gland secretory cells, implying that mixing of the proteases before co-packaging into secretory vesicles occurs at the beginning of protein synthesis in the RER cisternae.
authors.affiliation: Laboratório de Biologia Celular, Instituto Butantan, Av. Vital Brasil 1500, SP 05503-900, São Paulo, Brazil. sycarneiro@hotmail.com
authors.forename: Sylvia Mendes
authors.initials: SM
authors.lastname: Carneiro
authors.forename: Marina Tizuko
authors.initials: MT
authors.lastname: Assakura
authors.forename: Fernanda Angela Correia
authors.initials: FA
authors.lastname: Barrence
authors.forename: Silvia Regina Travaglia
authors.initials: SR
authors.lastname: Cardoso
authors.forename: Antonio Carlos
authors.initials: AC
authors.lastname: de Martins Camargo
authors.forename: Antonio
authors.initials: A
authors.lastname: Sesso
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D017837:Bothrops; D003435:Crotalid Venoms / Q000032:analysis; D005088:Exocrine Glands / Q000201:enzymology* / Q000648:ultrastructure; D008666:Metalloendopeptidases / Q000032:analysis*; D016253:Microscopy, Immunoelectron; D013379:Substrate Specificity; D014688:Venoms / Q000201:enzymology*
chemical_list: D003435:Crotalid Venoms; D014688:Venoms; D008666:Metalloendopeptidases; C472493:bothropasin, Bothrops jararaca; C068795:hemorrhagic factor LHFII