The PCR product was then subcloned between the BamH I and Sal I restrictions sites of a modified version of the yeast expression vector pEMBLyex4 that contains two Myc tags at the C-terminal end of the multiple cloning site (pC3852) generating the plasmid pC3853. The following primer combinations were used for cloning of vIF2α mutant constructs: vIF2αΔ59C: C27 plus C29 (5′- TAAAGTCGACCCGACCGACTCTGTCGAGGC-3′); Selumetinib mouse vIF2αΔ94C: C27 plus C30

(5′-TAAAGTCGACTCTCAGGGCCCTCACGGTCTC-3′); vIF2αΔ138C: C27 plus C31 (5′-TAAAGTCGACCTGATCGGCATTCACGGC-3′); vIF2α+26C: C27 plus C32 (5′-TAAAGTCGACCACAAAGGGGCACAGTCCTC-3′); vIF2αΔ94N: C33 (5′- PD0325901 TAGGATCCAAAATGGCCGATCAGGCGTACGAGTG-3′) plus C28; and vIF2αΔ94N+26C: C33 plus C32. The plasmid 8-Bromo-cAMP template for vIF2α+26C and vIF2αΔ94N+26C was generated by fusion PCR using vector primer C23 (5′- CATATGGCATGCATGTGCTCTG-3′) plus primer C21 (5′- GCCTTTACGACCTCTCGCACCTCAGACAGCACGGCGTGCAGTCCCCAGTAC GCCGCCTCAGAGTCGCCG-3′) for the first PCR and primer C22 (5′- GTGCGAGAGGTCGTAAAGGCTGCCGGGGGAGGACTGTGCCCCTTTGTGTA

AGTCGACCTGCAGGCATGC-3′) plus vector primer C24 (5′- CGCTTCCGAAAATGCAACGC-3′) for the second PCR. Following PCR purification, the two PCR products were mixed and used as a template for PCR along with the vector primers A46F (5′-ATTCTTTCCTTATACATTAGGTCC-3′) and A20R (5′-TGCTGCCACTCCTCAATTGG-3′). Finally, the PCR products were cloned into the BamHI and SalI sites of pEMBLyex4. All PCRs were carried out using Pfu Polymerase (Stratagene) and all plasmids were sequenced to verify correct sequences. Derivatives of pEMBLyex4 expressing VACV K3L (pC140) and VACV E3L (p2245), as well as the low copy-number SUI2, URA3 plasmid p919 were described previously [34, 40, 52]. Yeast strains were transformed

using the LiAcetate/PEG transformation method. For each transformation, four independent colonies were analyzed by streaking on inducing medium, SC-Gal minus uracil (synthetic complete medium containing 2% galactose and all amino acids, but lacking uracil) and grown at 30°C if not otherwise indicated. Protein expression and Western Blot analyses Yeast transformants were grown to saturation in 2 ml of SD medium. This starter culture was diluted through 1:50 in 25 ml SD medium and grown to OD600 = 0.6 and then shifted to SC-Gal medium to induce expression. After 13 hours, ODs of the cultures were measured and carefully adjusted by dilution in water to obtain comparable ODs and thus to lyse equivalent amounts of cells for each sample. Whole-cell extracts (WCEs) were prepared using the trichloroacetic acid (TCA) method as described previously [53] and then suspended in 200 μl 1.5 × loading buffer with reducing agent (both Invitrogen) and neutralized by the addition of 100 μl 1 M Tris base. Samples (5 μl) were fractionated on 10% Bis-Tris gels (Invitrogen), run in MOPS buffer (Invitrogen), and then transferred to nitrocellulose membranes.