The mouse Runx1 +23 hematopoietic stem cell enhancer confers hematopoietic specificity to both Runx1 promoters.
The transcription factor Runx1 plays a pivotal role in hematopoietic stem cell (HSC) emergence, and studies into its transcriptional regulation should give insight into the critical steps of HSC specification. Recently, we identified the Runx1 +23 enhancer that targets reporter gene expression to the first emerging HSCs of the mouse embryo when linked to the heterologous hsp68 promoter. Endogenous Runx1 is transcribed from 2 alternative promoters, P1 and P2. Here, we examined the in vivo cis-regulatory potential of these alternative promoters and asked whether they act with and contribute to the spatiotemporal specific expression of the Runx1 +23 enhancer. Our results firmly establish that, in contrast to zebrafish runx1, mouse Runx1 promoter sequences do not confer any hematopoietic specificity in transgenic embryos. Yet, both mouse promoters act with the +23 enhancer to drive reporter gene expression to sites of HSC emergence and colonization, in a +23-specific pattern.
Bee
Thomas
T
Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford University, United Kingdom.
Ashley
Emma L K
EL
Bickley
Sorrel R B
SR
Jarratt
Andrew
A
Li
Pik-Shan
PS
Sloane-Stanley
Jackie
J
Göttgens
Berthold
B
de Bruijn
Marella F T R
MF