AUTHOR=Malcom Carrie A. , Ratri Anamika , Piasecka-Srader Joanna , Borosha Shaon , Chakravarthi V. Praveen , Alvarez Nehemiah S. , Vivian Jay L. , Fields Timothy A. , Karim Rumi M.A. , Fields Patrick E. 

TITLE=Primitive Erythropoiesis in the Mouse is Independent of DOT1L Methyltransferase Activity

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2021.813503

DOI=10.3389/fcell.2021.813503

ISSN=2296-634X

ABSTRACT=<p>DOT1-like (DOT1L) histone methyltransferase is essential for mammalian erythropoiesis. Loss of DOT1L in knockout (<italic>Dot1l-</italic>KO) mouse embryos resulted in lethal anemia at midgestational age. The only recognized molecular function of DOT1L is its methylation of histone H3 lysine 79 (H3K79). We generated a <italic>Dot1l</italic> methyltransferase mutant (<italic>Dot1l-MM</italic>) mouse model to determine the role of DOT1L methyltransferase activity in early embryonic hematopoiesis. <italic>Dot1l-MM</italic> embryos failed to survive beyond embryonic day 13.5 (E13.5), similarly to <italic>Dot1l-</italic>KO mice. However, when examined at E10.5, <italic>Dot1l-MM</italic> embryos did not exhibit overt anemia like the <italic>Dot1l-KO</italic>. Vascularity and the presence of red blood cells in the <italic>Dot1l-MM</italic> yolk sacs as well as in the AGM region of <italic>Dot1l-MM</italic> embryos appeared to be similar to that of wildtype. In <italic>ex vivo</italic> cultures of yolk sac cells, <italic>Dot1l-MM</italic> primitive erythroblasts formed colonies comparable to those of the wildtype. Although <italic>ex vivo</italic> cultures of <italic>Dot1l-MM</italic> definitive erythroblasts formed relatively smaller colonies, inhibition of DOT1L methyltransferase activity <italic>in vivo</italic> by administration of EPZ-5676 minimally affected the erythropoiesis. Our results indicate that early embryonic erythropoiesis in mammals requires a DOT1L function that is independent of its intrinsic methyltransferase activity.</p>