1 1 Rift Valley fever virus MP-12 vaccine is fully attenuated by a combination of 2 partial attenuations in the S-, Mand L-segments 3 4

4 Tetsuro Ikegami,1,2,3* Terence E. Hill,1 Jennifer K. Smith,1,4 Lihong Zhang,1,4 Terry L. 5 Juelich,1,4 Bin Gong, 1,3,4 Olga A.L. Slack, 1† Hoai J. Ly, 1 Nandadeva Lokugamage, 1 6 Alexander N. Freiberg,1,2,3,4 7 8 Department of Pathology, The Sealy Center for Vaccine Development, The Center for 9 Biodefense and Emerging Infectious Diseases, Galveston National Laboratory, The 10 University of Texas Medical Branch at Galveston, 301 University Blvd. Galveston, Texas 11 77555 USA 12 13 Running title: RVFV MP-12 attenuation 14 15 *Address correspondence to Tetsuro Ikegami, Department of Pathology, University of 16 Texas Medical Branch, MMNP3.206D, 301 University Blvd. Galveston, TX 77555-0436. 17 Phone: (409)-772-2563. Fax: (409)-747-1763. E-mail: teikegam@utmb.edu. 18 19 Present address : Olga A.L. Slack, GlaxoSmithKline, 45 Sidney St. Cambridge, MA 20 02139 21 22