Structure and function analysis of the human myeloid cell nuclear differentiation antigen promoter: Evidence for the role of Sp1 and not of c-Myb or PU.1 in myelomonocytic lineage-specific expression

Abstract

The human myeloid nuclear differentiation antigen (MNDA) is expressed specifically in maturing cells of the myelomonocytic lineage and in monocytes and granulocytes. Epitope enhancement was used to confirm the strict lineage- and stage-specific expression of MNDA in bone marrow as well as in other paraffin-embedded fixed tissues. A 1-kb region of the gene that includes 5' flanking sequence was reported earlier to contain functional promoter activity and was specifically demethylated in expressing cells in contrast to null cells. Further analysis has revealed that this 1-kb fragment promotes higher reporter gene activity in MNDA-expressing cells than non-expressing cells, indicating cell-specific differences in transactivation. This sequence contains consensus elements consistent with myeloid-specific gene expression, including a PU.1 consensus site near the major transcription start site and a cluster of c-Myb sites located several hundred bases upstream of this region. However, analysis of deletion mutants localized nearly all of the promoter activity to a short region (-73 to -16) that did not include the cluster of c-Myb sites. A 4-bp mutation of the core Sp1 consensus element (GC box) (-20) reduced overall promoter activity of the 1-kb fragment. Mutation of the PU.1 site did not significantly affect promoter activity. Only a small region (-35 to +22) including the Sp1 element and transcription start site, but not the PU.1 site was footprinted. The 4-bp mutation of the core Sp1 consensus element abolished footprinting at the site and an antibody super-shift reaction showed that Sp1 is one of the factors binding the consensus site. The Sp1 site also co-localizes with a DNase I hypersensitive site. The results indicate that DNA methylation, chromatin structure, and transactivation at an Sp1 site contribute to the highly restricted expression of this myelomonocytic lineage specific gene.

The murine homolog of the HIN 200 family, Ifi 204, is constitutively expressed in myeloid cells and selectively induced in the monocyte/macrophage lineage

“…In the 5' flanking sequence of MNDA, several Myb and Ets binding elements are present, including an Ets-related PU.1 binding site known to be expressed specifically in M and B cells [28,34,35]. Analysis of the myeloid-specific CD11b promoter has indeed provided evidence that binding of both the PU.1 and the Sp1 transcription factor are required for its lineage-specific expression [36,37].…”

Mouse BTEB3, a new member of the basic transcription element binding protein (BTEB) family, activates expression from GC-rich minimal promoter regions

“…These sequences bind members of the zinc-finger family of transcription factors, and binding of these factors is required for maximal promoter activity [1][2][3][4]. The number of GC boxes and their spatial arrangement varies significantly between promoters.…”

Latency-Associated Nuclear Antigen of Kaposi's Sarcoma-Associated Herpesvirus Up-Regulates Transcription of Human Telomerase Reverse Transcriptase Promoter through Interaction with Transcription Factor Sp1

“…Telomerase is active in dividing cells, such as lymphocytes, keratinocytes, hematopoietic progenitor cells, and uterine endometrial cells, and in tumor-derived cell lines as well as malignant tissues (44,61,72). Human telomerase reverse transcriptase (hTERT), the enzymatic component of the telomerase, has been shown to be important and activated during cell immortalization and down-regulated during cell differentiation (39,48,61,79). Telomerase-positive cell lines and cancer cells have been shown to have an active hTERT promoter.…”