CHARACTERIZATION OF SMALL NONTRANSLATED POLYADENYLYLATED RNAS IN VACCINIA VIRUS-INFECTED CELLS

Host protein synthesis is selectively inhibited in vaccinia virus-infe cted cells. This inhibition has been associated with the production of a group of small, nontranslated, polyadenylylated RNAs (POLADS) produ ced during the early part of virus infection, The inhibitory function of POLADS is associated with the poly(A) tail of these small RNAs. To determine the origin of the 5'-ends of POLADS, reverse transcription w as performed with POLADS isolated from W-infected cells at 1 hr and 3. 5 hr post infection. The cDNAs of these POLADS were cloned into plasmi ds (pBS or pBluescript II KS +/-), and their nucleotide composition wa s determined by DNA sequencing. The results of this investigation show the following: There is no specific gene encoding for POLADS. The 5' ends of POLADS may be derived from either viral or cellular RNAs. Any RNA sequence including tRNAs, small nuclear RNAs and 5' ends of mRNAs can become POLADS if they acquire a poly(A) tail at their 3' ends duri ng infection. This nonspecific polyadenylylation found in vaccinia vir us-infected cells is probably conducted by vaccinia virus poly(A)(+) p olymerase. No consensus sequence is found on the 5' ends of POLADS for polyadenylylation. The 5' ends of POLADS have no direct role in their inhibitory activity of protein synthesis.