REGULATION OF THE CD13 AMINOPEPTIDASE-N GENE BY DMP1, A TRANSCRIPTIONFACTOR ANTAGONIZED BY D-TYPE CYCLINS/

The binding of the Myb-like DMP1 transcription factor to DNA consensus sequences [CCCG(G/T)ATGT] in artificial promoters is antagonized by D -type cyclins with no requirement for their catalytic partners, cyclin -dependent kinase (CDK) 4 and CDK6. The subset of DMP1 binding sites c ontaining the GGA core can bind Ets family transcription factors Ets-l and Ets-a. Screening of a series of natural promoters revealed that t he CD13/aminopeptidase N (APN; EC 3.4.11.2) promoter could bind and be activated by DMP1. Activation of CD13/APN required both the intact DN A binding and transactivation domains of DMP1 and was inhibited by D-t ype cyclins, but not by cyclins A, B, C, or H, in a CDK-independent ma nner, CD13/APN is transactivated by a cooperative interaction between c-Myb bound to its cognate site and Ets-l tethered to one of three GGA core-containing sites located 30-50 base pairs downstream. DMP1 binds to one of the Ets binding sites (designated Ets C) and synergizes wit h c-Myb in activating CD13/APN expression. Analysis of nuclear lysates from KG1a early myeloid cells using an oligonucleotide probe containi ng only the DMP1/Ets C binding site indicated that endogenous DMP1 and a putative Ets family member bind this element in vivo. DMP1-DNA comp lexes were significantly more stable than those containing the Ets fac tor. These data indicate that two different Myb family proteins collab orate in regulating APN gene expression and point to a role for DMP1 i n normal myeloid cell development.