Impaired myelopoiesis in mice lacking the repressors of translation initiation, 4E-BP1 and 4E-BP2.

Publication Type:

Journal Article

Source:

Immunology, Volume 128, Issue 1 Suppl, p.e376-84 (2009)

Keywords:

2009, Animals, Bone Marrow, Carrier Proteins, Cell Differentiation, Center-Authored Paper, Eukaryotic Initiation Factors, Granulocytes, MICE, Mice, Inbred BALB C, Mice, Knockout, Monocytes, Myelopoiesis, Phosphoproteins, Public Health Sciences Division, Spleen, Stem Cells, T-Lymphocytes, Thymus Gland

Abstract:

We investigated the role of two repressors of translation initiation in granulocytic differentiation using mice with a null mutation in the 4E-BP1 gene or with a null mutation in the 4E-BP2 gene. We show that 4E-BP1(-/-) and 4E-BP2(-/-) mice exhibit an increased number of immature granulocytic precursors, associated with a decreased number of mature granulocytic elements compared with wild-type mice, which is suggestive of an impaired granulocytic differentiation. Clonogenetic analyses revealed a reduced number of granulocytic colonies and concomitant increase in granulo-monocytic colonies in 4E-BP(-/-) mice. Finally, a slight expansion of monocytic cells was observed in the 4E-BP2(-/-) mice. In contrast, we did not observe any significant difference in thymocyte maturation in these mice. These results, together with the fact that 4E-BPs are markedly induced during granulo-monocytic differentiation of myeloid cells in vitro, highlight the pivotal role of 4E-BP1 and 4E-BP2 in the early phases of myelopoiesis. These results represent the first in vivo evidence of the involvement of translation in the early phases of granulo-monocytic differentiation and further extend the role of translation in haematopoietic differentiation.