Regulation of gene expression by the

1. An isolated nucleic acid sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 3, and fragments thereof, wherein the nucleic acid encodes a peptide that binds PlcR Box.

2. An isolated nucleic acid sequence encoding a polypeptide selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, and fragments thereof, wherein the encoded polypeptide binds PlcR Box.

3. A nucleic acid comprising a reporter gene operatively linked to a PlcR Box region of SEQ ID NO: 5.

4. The nucleic acid of claim 3 , wherein the reporter gene is a luciferase gene.

5. The nucleic acid of claim 3 , further comprising a nucleic acid sequence encoding a polypeptide selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, and fragments thereof, wherein the PlcR Box region is responsive to ARP1 and/or ARP2, and further wherein the encoded polypeptide binds PlcR Box.

6. A host cell comprising the nucleic acid of claim 5 , wherein the PlcR Box region is responsive to ARP1 and/or ARP2.

7. The host cell of claim 6 , wherein the host cell is a member selected from the group consisting of eukaryotic cells and prokaryotic cells.

8. A cell line stably transfected with the nucleic acid of claim 5 , wherein the PlcR Box region is responsive to ARP1 and/or ARP2.

9. A substantially purified polypeptide selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, and fragments thereof, wherein the polypeptide binds PlcR Box.

10. An isolated antibody or antibody fragment, wherein said antibody or antibody fragment selectively binds a polypeptide selected from the group consisting of:

a) an ARP polypeptide with an amino acid sequence of SEQ ID NO:2;

b) an ARP polypeptide with an amino acid sequence of SEQ ID NO:4;

c) an ARP polypeptide that is encoded by a nucleic acid molecule that hybridizes to the nucleic acid sequence of SEQ ID NO:1 under stringent conditions, comprising 50% formamide, 0.1% bovine serum albumin, 0.1% Ficoll, 0.1% polyvinylpyrrolidone, 50 mM sodium phosphate (pH 6.5), 750 mM NaCl, and 75 mM sodium citrate at 42° C., with washes at 42° C. in 0.2×SSC and 0.1% SDS; and

d) an ARP polypeptide that is encoded by a nucleic acid molecule that hybridizes to a nucleic acid sequence encoding SEQ ID NO:2 under stringent conditions, comprising 50% formamide, 0.1% bovine serum albumin, 0.1% Ficoll, 0.1% polyvinylpyrrolidone, 50 mM sodium phosphate (pH 6.5), 750 mM NaCl, and 75 mM sodium citrate at 42° C., with washes at 42° C. in 0.2×SSC and 0.1% SDS,

wherein the antibody or antibody fragment selectively binds to the ARP polypeptide and blocks the binding of ARP to PlcR Box.

11. The antibody of claim 10 , wherein said antibody is of polyclonal or monoclonal origin.

12. A recombinant cell whose genome comprises a recombinant DNA construct comprising a coding sequence encoding a polypeptide selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, and fragments thereof, wherein the polypeptide binds PlcR Box, and further wherein the recombinant cell is a member selected from the group consisting of eukaryotic cells and prokaryotic cells.

13. A method for producing the recombinant cell of claim 12 , comprising:

providing a cell selected from the group consisting of eukaryotic cells and prokaryotic cells;

providing a recombinant DNA construct comprising a coding sequence encoding a polypeptide selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 4, and fragments thereof, wherein the polypeptide binds PlcR Box;

transfecting the cell with the recombinant DNA construct,

thereby producing the recombinant cell.

14. A method of identifying a potential therapeutic agent for the treatment of anthrax infection which inhibits ARP-induced activation of the PlcR Box comprising the steps of:

(a) providing a reporter vector comprising a reporter gene and an PlcR Box region, wherein the PlcR Box region is responsive to ARP1 and/or ARP2;

(b) providing a test agent;

(c) providing ARP1 and/or ARP2;

(d) combining the reporter vector, the test agent, and ARP1 and/or ARP2;

(e) measuring reporter gene activity in the presence of test agent;

(f) measuring reporter gene activity in a control sample without test agent; and

(g) comparing reporter gene activity in the control sample compared to the test sample, to identify a compound which modulates PlcR Box activity.

15. The method of claim 14 , wherein the reporter vector comprising a reporter gene and the PlcR Box region responsive to ARP1 and/or ARP2 is in a stably transfected cell line.

16. The method of claim 15 , wherein the cell line is a member selected from the group consisting of eukaryotic cells, and prokaryotic cells.

17. The method of claim 14 , wherein the reporter gene is a luciferase gene.

18. A kit comprising a reporter vector comprising a PlcR Box, wherein the PlcR Box is responsive to ARP1 and/or ARP2.