Title: High efficiency of alphaviral gene transfer in combination with 5-fluorouracil in a mouse mammary tumor model The short title: Alphavirus-mediated transgene expression in combination with 5-FU Authors:

1. Department of Cell Biology, Biomedical Research and Study Centre, Riga, Latvia 2. P. Stradins Clinical University Hospital, Riga, Latvia 3. Latvian Institute of Organic Synthesis, Riga, Latvia * equal contribution Correspondence: Dr Anna Zajakina, Department of Protein Engineering, Biomedical Research and Study Centre, Ratsupites Str., 1, Riga LV-1067, Latvia, Phone: 371 7808004, Fax number: 371 7442407, E-mail: [email protected] email addresses for all authors, respectively: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected];