A role for RNA polymerase II tracking in β-globin locus transcriptional regulation

Friday, November 08, 2013 — Poster Session III
10:00 a.m. – 12:00 p.m.	FAES Academic Center (Upper-Level Terrace)	NIDDK	CHROM-6

Authors

JH Oum
A Nguyen
A Dean

Abstract

The mouse β-globin locus contains embryonic ey and β-h1 genes and adult β-major and β-minor genes. Activation of all the genes requires the locus control region (LCR) 60 kb upstream of β-major but only 6 kb from ey. Chromatin looping occurs between the LCR and β-major but whether this mechanism also activates the more proximal ey gene is unclear. We investigated the hypothesis that pol II tracks along chromatin from the LCR to ey by inserting a transcription terminator on one allele of mouse ES cells by recombination. We differentiated WT and terminator ES cells and determined D-allelic specific expression. In terminator bearing ES cells, ey was dramatically reduced on day 9 of differentiation compared to WT. In contrast, β major transcripts that appear later in differentiation were the same in both types of cells. These results raise the possibility that the LCR may employ different mechanisms to activate globin gene transcription at different developmental stages. Currently we monitor intergenic transcripts and RNA pol II occupancy between the LCR and ey globin gene in WT and terminator bearing ES cells. To further understand of LCR mechanisms in vivo, we generate mouse lines bearing the transcription terminator in the β-globin locus.