Transcriptional interference and termination between duplicated α-globin gene constructs suggests a novel mechanism for gene regulation

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Abstract
The interesting possibility that transcriptional interference can occur between eukaryotic genes was raised by studies on the avian leukosis retrovirus (ALV)1 which showed that deletion of the promoter in the 5′ long terminal repeat (LTR) activates the 3′ LTR promoter, linked to a downstream gene. These observations provide a molecular explanation for the fact that insertional oncogenesis by the ALV promoter is invariably associated with either a rearranged or deleted 5′ LTR sequence2‐4. This letter extends these findings to chromosomal RNA polymerase II genes by studying transcriptional interference between duplicated α-globin gene constructions. I demonstrate that transcriptional interference causes substantial inhibition of the downstream α gene by transcription of the upstream α gene. Furthermore, this inhibition is alleviated by placing transcriptional termination signals between the two α genes. Because many eukaryotic genes may be arranged in tandem on a chromosome, these observations suggest that transcriptional termination is an important mechanism for preventing interference between adjacent genes. The selective use of termination signals may provide a novel way of regulating the activity of eukaryotic genes.