RNeasy Micro Kit (Qiagen, Valencia, CA); a mixture of oligo(dT 15 ) and random hexamers (pdN6) as primers; and AMV reverse transcriptase (Promega, Madison, WI) as previously described [4, 20] . In vitro transcribed and infected cell RNA templates represent in vitro and in vivo replication, respectively. PCR amplification with HAV or CV specific primers was carried out in 50 l reactions using 5 l of each RT reaction as template or 5ng of pHAV/7 plasmid DNA as previously described [20] . PCR products (5 l) were analyzed by agarose gel electrophoresis to confirm authenticity of product formation (data not shown).