Figure 8

Representation of the active copies of the Ens-1 LTR on the main chicken chromosomes and potential consequences. (A) Density along the chromosomes 1 to 5 and z, of active solo-LTR (in blue) and inactive solo-LTR (in red) based on the sequence of the four activation motifs. The blue arrows indicate individual active solo-LTR inserted near genes. Distance in Megabases is indicated on the left scale. The black arrows indicate the position of each centromere. The purple line on the chromosome 1 indicates the position of the Nanog gene. (B) Combinations of intact binding sites that recruit transcription factors and may support LTR activity. The expected expression pattern in the epiblast and in the hypoblast is indicated for the transcripts induced by each type of LTR. Functional interpretation of each expression pattern is also mentioned. In situation 2, LTR activity is increased by Ets binding but depends on Nanog.