Rat sperm rosettes: Identification of epididymal proteins involved in sperm rosettes assembling

MONCLUS MA; CABRILLANA ME; CESARI, A; VINCENTI AE; FORNÉS MW

Villa Carlos Paz, Cordoba, Argentina

Congreso; XLIV Reunion Annual SAIB; 2008

Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular

In many mammals? species, sperm associate during their epididymal trip. This association could be related to sperm maturation and protection during epididymal storage. In the rat these association were called Rosettes and appeared in the distal cauda. The aim of this work was isolate proteins from caudal epididymal fluid (EF) with activity to re associate sperm in vitro trying to mimic the in vivo phenomenon (in vitro sperm re association test: i.v. Rosette test). Mature and motile sperm (1.106 cells/ml) was incubated with EF fractions (1 mg/ml) and the number of Rosettes obtained in vitro was recorded (expressed as Rosettes number/60 microscopic fields, 400 X). Using gel filtration ?proteins separated by size range (Sephacryl S200) - and affinity chromatographies ?Glucose/mannose affinity proteins fractionation (Concanavalin A sepharose) - EF was fractionated in eight fractions. All fractions were tested by i.v. Rosettes test and the most active fraction (with MW from 40 to 80 KDa) and Concanavalin A affinity were analysed by MALDI-TOF-MS. Two proteins with serine protease inhibitor activity (serpins) were identified: á1-Antitrypsin and a new protein with a á1-Antitrypsin like domain. These results and previous indicate that Rosettes are assembled during the epididymal trip by several factors: sperm motility inhibition, linking proteins, proteases and their inhibitors.