Hyaluronan synthesis in virus PBCV-1-infected chlorella-like green algae

We previously reported that the chlorella virus PBCV-1 genome encodes an au thentic, membrane-associated glycosyltransferase, hyaluronan synthase (HAS) . Hyaluronan, a linear polysaccharide chain composed of alternating beta 1, 4-glucuronic acid and beta 1,3-N-acetylglucosamine groups, is present in Ve rtebrates as well as a few pathogenic bacteria. Studies of infected cells s how that the transcription of the PBCV-1 has gene begins within 10 min of v irus infection and ends at 60-90 min postinfection. The hyaluronan polysacc haride begins to accumulate as hyaluronan-lyase sensitive, hair-like fibers on the outside of the chlorella cell wall by 15-30 min postinfection; by 2 40 min postinfection, the infected cells are coated with a dense fibrous ne twork. This hyaluronan slightly reduces attachment of a second chlorella vi rus to the infected algae. An analysis of 41 additional chlorella viruses i ndicates that many, but not all, produce hyaluronan during infection. (C) 1 999 Academic Press.