PIF/harbinger transposon-derived protein promotes 7SL expression to enhance pathogen resistance.

Transcriptional regulation governs gene expression levels, primarily controlled by "cis-acting DNA elements" and "trans-acting protein factors". However, the conventional view that cis-regulation is solely attributable to DNA elements is challenged in this study. Our research indicates that transposon-derived proteins may retain their original DNA-binding preference and exert cis-regulatory effects on nearby genes on the chromosome, thus denoted as "cis-acting factors". Specifically, we show that the ADF-1L protein, derived from the PIF/harbinger transposon, recruits the histone acetyltransferase KAT2B in a MADF domain-dependent manner, facilitating its own nuclear translocation and binding to and cis-regulating its own and adjacent gene 7SL-23. ADF-1L protein also boosts the host's resistance to pathogens by promoting the expression of immune molecule 7SL RNA. In summary, our findings expand the types of molecules that can exert cis-function in gene regulation and underscore the relevance of transposons-derived sequences in cellular processes.