Serine palmitoyltransferase (scs1/lcb2) mutants have elevated copy number of the L-A dsRNA virus

The microsomal fraction isolated from serine palmitoyltransferase (lcb2/scs1) mutants is enriched in a 90 kDa protein. The protein was identified as the major coat (Gag) protein of the L-A dsRNA virus particles by partial sequencing and by its interaction with anti-Gag antibodies. The total amount of Gag in whole-cell lysates of scs1/lcb2 mutant cells is greater than in wild-type lystes indicating that the enrichment of the protein in the microsomal fraction of scs1/lcb2 mutant cells may result from increased copy number of the L-A dsRNA virus. This is supported by the finding that the mutants also have increased levels of L-A dsRNA. Altered sphingolipid synthesis in the scs1 mutant cells appears to increase the copy number of the L-A viral particles.