Distinct Domains of the GATA-1 Cofactor FOG-1 Differentially Influence Erythroid versus Megakaryocytic Maturation

Abstract

FOG family zinc finger proteins play essential roles in development through physical interaction with GATA factors. FOG-1, like its interacting partner GATA-1, is required for normal differentiation of erythroid and megakaryocytic cells. Here, we have developed a functional assay for FOG-1 based on its ability to rescue erythroid and megakaryocytic maturation of a genetically engineered FOG-1^−/− cell line. We demonstrate that interaction through only one of FOG-1's four GATA-binding zinc fingers is sufficient for rescue, providing evidence against a model in which FOG-1 acts to bridge multiple GATA-binding DNA elements. Importantly, we find that distinct regions of FOG-1 differentially influence erythroid versus megakaryocyte maturation. As such, we propose that FOG-1 may modulate the fate of a bipotential erythroid/megakaryocytic precursor cell.

The first two authors contributed equally to this work.

We thank Robert Hawley and Richard Mulligan for generously providing us with the HOX-11 retroviral producer cell line and the MMP retroviral vector system, respectively. We thank Merlin Crossley for providing FOG-1 tyrosine-to-alanine point mutant constructs. We also thank Christoph Klein and Hanno Hock for advice on retroviral production and infection and John Daley for his assistance with fluorescence cell sorting.

A.B.C. is supported by National Institutes of Health grant 5K08CA82175. Support was also derived from an NIH grant to S.H.O. S.H.O. is an Investigator of the Howard Hughes Medical Institute.