Purification of retrovirus genomic RNA suitable for chemical radioiodination.

An efficient method for the purification of genomic RNA from the retrovirus, caprine arthritis-encephalitis virus, is described. The method utilizes proteinase K, extraction with sodium perchlorate and chromatography on oligo(dT)-cellulose and results in highly purified RNA capable of being chemically iodinated with Na125 I to high specific radioactivity. The iodinated RNA exhibits 80-90% precipitability in 5% trichloroacetic acid and is greater than or equal to 99% sensitive to hydrolysis by ribonuclease. Several alternative methods which are effective for the preparation of eukaryotic ribosomal RNA are unreliable for purification of retrovirus RNA suitable for radioiodination.