<p>Cells were mock-infected or infected with MHV-A59, one of the <i>ts</i> mutants, or with a mixture of two <i>ts</i> mutants. The cells were incubated at 40 °C in medium containing dactinomycin and <sup>3</sup>H-uridine and, at 8 hpi, <sup>3</sup>H-uridine incorporation into trichloroacetic acid-precipitated RNA was determined. Cells were infected with: M, mock-infected; A59, MHV-A59; A6, Alb <i>ts</i>6; A16, Alb <i>ts</i>16; A22, Alb <i>ts</i>22; A17, Alb <i>ts</i>17; L6, LA <i>ts</i>6; W18, Wü <i>ts</i>18; W36, Wü <i>ts</i>36; W38, Wü <i>ts</i>38; A6xA16, Alb <i>ts</i>6 and Alb <i>ts</i>16; A6xL6, Alb <i>ts</i>6 and LA <i>ts</i>6; A6xA22, Alb <i>ts</i>6 and Alb <i>ts</i>22; A16xL6, Alb <i>ts</i>16 and LA <i>ts</i>6; A16xA22, Alb <i>ts</i>16 and Alb <i>ts</i>22; L6xA22, LA <i>ts</i>6 and Alb <i>ts</i>22; A17x A16, Alb <i>ts</i>17 and Alb <i>ts</i>16; A17xL6, Alb <i>ts</i>17 and LA <i>ts</i>6; A17xA22 or A22xA17, Alb <i>ts</i>17 and Alb <i>ts</i>22; A17xW38, Alb <i>ts</i>17 and Wü <i>ts</i>38; A17xW18, Alb <i>ts</i>17 and Wü <i>ts</i>18; A17xW36, Alb <i>ts</i>17 and Wü <i>ts</i>36; A22xW18, Alb <i>ts</i>22 and Wü <i>ts</i>18; A22xW36, Alb <i>ts</i>22 and Wü <i>ts</i>36; A22xW38, Alb <i>ts</i>22 and Wü <i>ts</i>38; W18xW36, Wü <i>ts</i>18 and Wü <i>ts</i>36; W18xW38, Wü <i>ts</i>18 and Wü <i>ts</i>38; W36xW38, Wü <i>ts</i>36 and Wü <i>ts</i>38.</p
