Cloning and characterisation of a delta virus cDNA sequence derived from a human source.

We report the extraction of delta virus RNA from the serum of a delta-virus-infected patient and the subsequent cloning and analysis of a 380-nucleotide-long cDNA (D380). The nucleotide sequence of D380 shows overall differences of approximately 20% when compared with previously published sequences and does not include the viroid consensus sequence previously reported (Wang et al: Nature 323:508-514, 1986). A potentially coding open reading frame extending over the whole length of the D380 has been identified. Our results demonstrate the existence of genetic heterogeneity amongst different delta virus isolates.