Gender-enriched transcription of activation associated secreted proteins in Ostertagia ostertagi q A. Visser a, * , A.M. Van Zeveren a , Y. Meyvis a , I. Peelaers a , W. Van den Broeck b , K. Gevaert c , J. Vercruysse a , E. Claerebout a , P. Geldhof a a Laboratory of Parasitology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B9820 Merelbeke, Belgium b Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B9820 Merelbeke, Belgium c Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology, Ghent University, Merelbeke, Belgium Received 18 June 2007; received in revised form 17 August 2007; accepted 21 August 2007 Abstract Activation associated secreted proteins (ASP) are members of a nematode-specific protein family belonging to the SCP/Tpx-1/Ag5/ PR-1/Sc7 family. Three different types of molecules have been identified in this family: two-domain ASPs and single-domain ASPs show- ing homology to either the C-terminal or N-terminal domain of the two-domain ASP. The function of these proteins is still unclear, but a role in transition to parasitism and a role as allergen are often suggested. Here we report that the abomasal cattle parasite Ostertagia ostertagi produces at least 15 ASPs, including two-domain and C- and N-type single-domain ASPs. Ten of these are highly transcribed in the L4 stage, whereas others are highly enriched in adult male worms. The latter was especially the case for the N-type single-domain ASPs Oo-ASP1 and Oo-ASP2 and also for Oo-ASP3, which is homologous with the Haemonchus contortus and Ancylostoma caninum C- type single-domain ASPs. Immunohistochemistry showed that Oo-ASP3 was localised in the oesophagus. Oo-ASP1 and Oo-ASP2 on the other hand were localised in the reproductive tract of both male and female worms, suggesting a role in reproduction or in the devel- opment of the reproductive tract. Ó 2007 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved. Keywords: Ostertagia; ASP; Reproduction; Activation associated secreted proteins 1. Introduction Activation associated secreted proteins (ASPs) have been described in a wide variety of parasitic nematodes such as Ancylostoma caninum (Hawdon et al., 1996, 1999; Bin et al., 2003), Ancylostoma duodenale (Bin et al., 1999),Ancy- lostoma ceylanicum (Goud et al., 2004), Necator americanus (Bin et al., 1999; Daub et al., 2000; Asojo et al., 2005), Onchocerca volvulus (Tawe et al., 2000), Brugia malayi (Murray et al., 2001), Haemonchus contortus (Schallig and Van Leeuwen, 1997; Schallig et al., 1997a,b; Rehman and Jasmer, 1998), Cooperia punctata (Yatsuda et al., 2002) and Ostertagia ostertagi (Geldhof et al., 2003). They are of general interest as they have shown their protective capacity in multiple vaccination trials against Ancylostoma spp., H. contortus and O. ostertagi (Schallig et al., 1997a; Ghosh and Hotez, 1999; Geldhof et al., 2002, 2004; Goud et al., 2004; Meyvis et al., 2007). Three types of ASP pro- teins have been identified in nematodes: long ASP proteins composed of two distinct but related domains and short ASP molecules that show similarity to either the C-terminal or the N-terminal domain of the double-domain ASP. The two-domain and the C-type single-domain ASPs were orig- inally identified in H. contortus (named Hc40 and Hc24, respectively) and A. caninum (ASP1 and ASP2) (Hawdon et al., 1996, 1999; Schallig et al., 1997b; Rehman and Jasmer, 1998). These two types seem to be very common and homologues have been described in all the parasites 0020-7519/$30.00 Ó 2007 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijpara.2007.08.008 q Nucleotide sequence data reported in this paper are available in the GenBank, EMBL and DDBJ databases under the Accession Nos. AM747038, AM747039. * Corresponding author. Tel.: +32 9 2647404; fax: +32 9 2647496. E-mail address: Aline.Visser@Ugent.be (A. Visser). www.elsevier.com/locate/ijpara Available online at www.sciencedirect.com International Journal for Parasitology 38 (2008) 455–465