Figure 2.

Summary of the 5′ RACE experiments. (A) Strategy for determination of the 5′ end of the viral RNA. HERV-K full-length and spliced RNAs are schematically shown with the gag, PR, pol, env, and rec/np9 genes (top). Experimental processes are illustrated with gene specific primers. (B) Products detected in the experiments. (1) Detection of the transcriptional start points in HERV-K LTR. Twenty-one of 50 clones contained a 3′ terminal region of the 5′ LTR followed by the leader sequences. (2) Expression of a HERV-K-like element rearranged by the loss of 5′ LTR and a 3.6-kb deletion spanning pol and env. The transcripts without a LTR sequence were aligned with the segmented HERV-K locus at 7q22. Twenty-four of fifty 5′ RACE clones contained this structure.