The C-terminal zinc finger of GATA-1 or GATA-2 is sufficient to induce megakaryocytic differentiation of an early myeloid cell line.
The GATA-1 and GATA-2 transcription factors, which each contain two homologous zinc fingers, are important hematopoietic regulators expressed within the erythroid, mast cell, and megakaryocytic lineages. Enforced expression of either factor in the primitive myeloid line 416B induces megakaryocytic differentiation. The features of their structure required for this activity have been explored. The ability of 12 GATA-1 mutants to promote 416B maturation was compared with their DNA-binding activity and transactivation potential. Differentiation did not require any of the seven serine residues that are phosphorylated in vivo, an N-terminal region bearing the major transactivation domain, or a C-terminal segment beyond the fingers. Removal of a consensus nuclear localization signal following the second finger did not block differentiation or nuclear translocation. The N-terminal finger was also dispensable, although its removal attenuated differentiation. In contrast, the C-terminal finger was essential, underscoring its distinct function. Remarkably, only 69 residues spanning the C-terminal finger were required to induce limited megakaryocytic differentiation. Analysis of three GATA-2 mutants led to the same conclusion. Endogenous GATA-1 mRNA was induced by most mutants and may contribute to differentiation. Because the GATA-1 C-terminal finger could bind its target site but not transactivate a minimal reporter, it may direct megakaryocytic maturation by derepressing specific genes and/or by interacting with another protein which provides the transactivation function.
Visvader
J E
JE
Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia.
Crossley
M
M
Hill
J
J
Orkin
S H
SH
Adams
J M
JM
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D003001:Cloning, Molecular; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000502:physiology*; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D050989:GATA2 Transcription Factor; D015870:Gene Expression; D005822:Genetic Vectors; D008533:Megakaryocytes / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D015183:Restriction Mapping; D017384:Sequence Deletion; D014157:Transcription Factors / Q000096:biosynthesis / Q000502:physiology*; D015533:Transcriptional Activation; D014162:Transfection; D016335:Zinc Fingers
D017931:DNA Primers; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D050989:GATA2 Transcription Factor; C494689:Gata1 protein, mouse; C494712:Gata2 protein, mouse; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014157:Transcription Factors