Coronavirus induction of class I major histocompatibility complex expression in murine astrocytes is virus strain specific

Coronavirus Induction of Class I MHC Expression Is Virus Strain Specific proteins S, M, and N in addition to two nonstructural proteins, which suggests that the class I-inducing activity resides in one of these proteins. Often, though not exclusively, the most potent inducers of class I were strains that retain the highest percentage of A59 sequences at the 3' end, while those retaining the least A59 character, or exhibiting more than one crossover site for recombination, were significantly less potent. In addition, it was observed in three out of four experiments that RL1 was •50% less potent than EL3, as illustrated in Fig. 3 B. EL3 retains slightly more A59 sequences in the S gene than RL1. This observation suggests that class I-inducing activity may involve S. However, it was not possible to attribute the class I-stimulating activity to an individual gene or gene product, since none of the recombinants had crossover sites that sufficiently isolated individual A59 from JHMV genes. However, it was clear that ifJHMV sequences were retained at the 3' end, class 1-inducing activity was abolished, and that 5' retention of A59 sequences did not salvage it.