BK virus DNA cloned directly from human urine confirms an archetypal structure for the transcriptional control region.

A BK virus isolate cloned from the urine of an immunosuppressed patient was identified as the WW strain. Fine mapping using four base-pair restriction enzymes identified a number of small deletions and insertions relative to prototype BK. The finding of a transcriptional control region with a structure similar to that of a previous isolate cloned in a similar way demonstrates that this is a reproducible finding and reinforces the hypothesis that the structure is the archetypal form, found when cloned directly from urine, but generally altered when passaged in cell culture. BK virus is a human papovavirus first identified in the urine of a renal allograft patient by Gardner. Several BK strains have been studied in detail by restriction endonuclease mapping or sequencing. Two of these, the Dunlop and the MM strains, have been sequenced in their entirety, and a 400 to 500 base-pair region concerned with the control of transcription and replication has been sequenced in a number of others. All of these BK virus isolates were amplified by passage in cell culture before being characterized, although it often takes many weeks in culture before plaques can be identified and it has been reported that genome changes can occur on passage. Previous to the present isolate, we have identified BK virus in the urine of three local patients, and limited restriction endonuclease analysis of DNA prepared directly from the urine showed that they were similar and represented a new strain (BK-WW).(ABSTRACT TRUNCATED AT 250 WORDS)