UBF Is An Epigenetic Factor Required For Ribosomal RNA Gene Activity And Preinitiation Complex Assembly But Not For Nucleolar Body Formation

Upstream Binding Factor (UBF) is a unique multi-HMGB-box protein first identified as a co-factor in RNA polymerase I (RPI/PolI) transcription. However, its poor DNA sequence selectivity and its ability to generate nucleosome-like nucleoprotein complexes suggest a more generalized role in chromatin structure. We previously showed that extensive depletion of UBF reduced the number of actively transcribed ribosomal RNA (rRNA) genes, but had little effect on rRNA synthesis rates or cell proliferation, leaving open the question of its requirement for RPI transcription. Using conditional gene deletion in mouse, we now show that UBF is indeed essential for transcription of the rRNA genes.

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Hamdane N, Stefanovsky VY, Tremblay MG, Németh A, Paquet E, Lessard F, Sanij E, Hannan R, Moss T