The Brn-5 protein, highly expressed in human brain, belongs to the POU family; a
class of transcription factors involved in a wide variety of biological
processes ranging from programming of embryonic stem cells to cellular
housekeeping. This functional diversity is conferred by two DNA-binding
subdomains that can assume several configurations due to a bipartite arrangement
of POU-specific (POU(S)) and POU-homeo (POU(H)) subdomains separated by a linker
region. The crystal structure of human Brn-5 transcription factor in complex
with corticotrophin-releasing hormone (CRH) gene promoter reveals an unexpected
recognition mode of the protein to its cognate DNA. Moreover, the structure also
shows the role of the linker in allowing diverse configurations that can be
assumed by the two subdomains.
