TRANSCRIPTIONAL ANALYSIS AND GENOME EXPRESSION OF CHICKEN ANEMIA VIRUS

Strand-specific riboprobes representative of either strand of the chic ken anaemia virus (CAV) replicative form (RF) DNA indicated that only one strand of the RF was transcribed to produce a major 2.0 kb transcr ipt and that the encapsidated DNA strand was of negative sense. Primer extension analysis located a single transcriptional start site at nuc leotide position 360 of the CAV sequence. Amplification, cloning and s equencing of the 3' end of the major transcript revealed the polyadeny lation site at nucleotide position 21. Northern blot analysis using a series of genomic probes indicated that the 2.0 kb transcript was devo id of splicing and identified a non-transcribed region of the genome. This nontranscribed region was shown to possess promoter activity, enh ancing the expression of the human growth hormone reporter gene in a t ransient gene expression assay. These observations suggest a simple st rategy of genome expression involving a functional polycistronic messa ge.