Compositions and methods for regulating sas1r

Abstract

The present invention provides compositions and methods useful for regulating fertilization and for use as a contraceptive based on the discovery herein of an oocyte specific protein, SAS1R (Sperm Acrosomal SLLP1 Receptor), which is a sperm protein receptor. Six SAS1R variants, including the full length SAS1R, were identified. mSLLP1 and SAS1R co-localized to oocytes and to acrosomes of acrosome-reacted sperm. Interactions between mSLLP1 and SAS1R were demonstrated by far-western analysis, in a yeast two-hybrid system under stringent selection conditions, and by immunoprecipitation of SAS1R by anti-mSLLP1 as well as the converse. Purified recombinant SAS1R was found to have protease activity, to inhibit fertilization in-vitro, and to induce an immune response in females. Together, the results suggest SAS1R is a proteolytically active, oocyte and early embryo specific oolemmal metalloprotease receptor for the sperm intra-acrosomal ligand SLLP1 and is a target for regulating fertilization and as a contraceptive.

1 . A method of inhibiting fertilization comprising:
 contacting an egg with a pharmaceutical composition containing an effective fertilization-inhibiting amount of at least one inhibitor of SAS1R and a pharmaceutically-acceptable carrier;   wherein said at least one inhibitor of SAS1R is selected from the group consisting of an antibody directed against SAS1R and purified SAS1R or a fragment or homolog thereof,   wherein the antibody is obtained by immunizing a host animal by injection with the SAS1R and purified SAS1R or a fragment or homolog thereof,   wherein SAS1R has a sequence selected from the group consisting of SEQ ID NOs: 6, 8, 10, 19, 20 and 21;   wherein the fragment of SAS1R comprises amino acids selected from the group consisting of 1-25, 26-50, 51-75, 76-100, 101-125, 126-150, 151-175, 176-200, 201-225, 226-250, 251-275, 276-300, 301-325, 326-350, 351-375, 376-400, and 401-414 of SAS1R Variant 2 (SEQ ID NO: 6); or selected from the group consisting of 1-25, 26-50, 51-75, 76-100, 101-125, 126-150, 151-175, 176-200, 201-225, 226-250, 251-275, 276-300, 301-325, 326-350, 351-375, 376-400, 401-425, and 426-435 of SAS1R Variant 1 (SEQ ID NO: 19); and   wherein the homolog has at least 90% amino acid sequence identity with SAS1R.   
     
     
         2 . The method of  claim 1 , wherein said at least one inhibitor of SAS1R inhibits SAS1R protease activity. 
     
     
         3 . The method of  claim 1 , wherein said at least one inhibitor of SAS1R inhibits the interaction of SAS1R with a SLLP protein. 
     
     
         4 . The method of  claim 3 , wherein said at least one inhibitor of SAS1R is a SAS1R protein, or a fragment or homolog thereof. 
     
     
         5 - 10 . (canceled) 
     
     
         11 . The method of  claim 4 , wherein at least two different proteins, or homologs, fragments, or derivatives thereof are administered. 
     
     
         12 . The method of  claim 11 , wherein the proteins, or homologs and fragments, thereof are administered in a mixture of approximately equimolar concentrations. 
     
     
         13 . The method of  claim 4 , wherein the amount of protein, or fragments or homolog thereof administered is between about 0.001 mg/kg body weight and about 100 mg/kg body weight. 
     
     
         14 . The method of  claim 1 , wherein said method is reversible. 
     
     
         15 - 16 . (canceled) 
     
     
         17 . A method of inducing an immune response in a subject wherein said response is directed to an immunogenic oocyte stage specific metalloprotease sperm protein receptor, further wherein inhibition of said metalloprotease inhibits fertilization, said method comprising administering to the subject a pharmaceutical composition comprising an effective immune response-inducing amount of a protein comprising an amino acid sequence encoding SAS1R or a fragment or homolog thereof, thereby inducing an immune response in a subject. 
     
     
         18 . (canceled) 
     
     
         19 . The method of  claim 17 , wherein said SAS1R has an amino acid sequence selected from the group consisting of SEQ ID NOs:6, 8, 10, 19, 20, 21, and 23. 
     
     
         20 . The method of  claim 17 , said pharmaceutical composition further comprising an adjuvant. 
     
     
         21 . The method of  claim 17 , said pharmaceutical composition comprising more than one SAS1R fragment or homolog thereof. 
     
     
         22 . The method of  claim 17 , wherein said immune response inhibits fertilization. 
     
     
         23 - 33 . (canceled) 
     
     
         34 . A contraceptive target comprising an immunogenic oocyte stage specific metalloprotease, wherein:
 said oocyte specific metalloprotease functions in fertilization;   said oocyte stage specific metalloprotease is a sperm protein receptor;   said oocyte stage specific metalloprotease is found specifically in secondary and subsequent follicular stages;   inhibition of said target will not affect oocyte stem cells, including naked, primordial, and primary oocytes; and   inhibition of said target inhibits fertilization.   
     
     
         35 . (canceled) 
     
     
         36 . The contraceptive target of  claim 34 , wherein said contraceptive target is SAS1R. 
     
     
         37 . The composition of  claim 36 , wherein SAS1R has a sequence selected from the group of amino acid sequences consisting of SEQ ID NOs 6, 8, 10, 19, 20, 21, and 23, or a fragment or homolog thereof. 
     
     
         38 . The contraceptive target of  claim 36 , wherein said oocyte stage specific metalloprotease comprises a sequence selected from the group of amino acid sequences consisting of SEQ ID Nos: 6, 8, 10, 19, 20, 21, and 23, or a fragment or homolog thereof, interacts with a SLLP protein. 
     
     
         39 . The contraceptive target of  claim 38 , wherein said SLLP protein is SLLP1. 
     
     
         40 - 41 . (canceled) 
     
     
         42 . The method of  claim 1 , wherein the host animal is a rabbit, mouse, or rat. 
     
     
         43 . The method of  claim 1 , wherein the method is carried out in vitro.