Open AccessThe Regulation of rRNA Gene Transcription during Directed Differentiation of Human Embryonic Stem Cells
Author(s) -
Jessica L. Woolnough,
Blake L. Atwood,
Ling Zhong,
Rui Zhao,
Keith E. Giles
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0157276
Subject(s) - biology , embryonic stem cell , induced pluripotent stem cell , cellular differentiation , stem cell , ribosomal rna , microbiology and biotechnology , gene expression , regulation of gene expression , gene , genetics
It has become increasingly clear that proper cellular control of pluripotency and differentiation is related to the regulation of rRNA synthesis. To further our understanding of the role that the regulation of rRNA synthesis has in pluripotency we monitored rRNA synthesis during the directed differentiation of human embryonic stem cells (hESCs). We discovered that the rRNA synthesis rate is reduced ~50% within 6 hours of ACTIVIN A treatment. This precedes reductions in expression of specific stem cell markers and increases in expression of specific germ layer markers. The reduction in rRNA synthesis is concomitant with dissociation of the Pol I transcription factor, UBTF, from the rRNA gene promoter and precedes any increase to heterochromatin throughout the rRNA gene. To directly investigate the role of rRNA synthesis in pluripotency, hESCs were treated with the Pol I inhibitor, CX-5461. The direct reduction of rRNA synthesis by CX-5461 induces the expression of markers for all three germ layers, reduces the expression of pluripotency markers, and is overall similar to the ACTIVIN A induced changes. This work indicates that the dissociation of UBTF from the rRNA gene, and corresponding reduction in transcription, represent early regulatory events during the directed differentiation of pluripotent stem cells.