Fig. 3
From: Genetic Evolution during the development of an attenuated EIAV vaccine
Alteration of the transcription factor binding motifs in the LTR U3 region. Sequences of 134 clones of the LTR from seven EIAV strains were randomly isolated from PCR-amplified fragments and analyzed. NRE indicates the negative regulation element and EHR indicates the enhancer region. The boxes define transcription factor binding sites. The numbers at the left end of the gray lines indicate the detected clones of each strain. The numbers in parentheses refer to the numbers of clones that contain the indicated transcription factor binding site