Oct-1 Is Involved in the Transcriptional Repression of the von Willebrand Factor Gene Promoter

Abstract

The negative regulation of transcription of the human von Willebrand factor (vWF) gene was investigated in human umbilical vein endothelial cells (HUVECs) and HeLa cells. A fragment spanning −89 to +244 nucleotides (nt), containing the first exon, is active in HUVECs only but not in HeLa cells. The activity of this promoter is sharply reduced by mutagenesis of the GATA binding site at +221. Extension of the upstream sequences from nt −89 to −142 and to −496 results in progressive reduction of the activity of the −89 to +244 promoter identifying a negative regulatory element between nt −142 and −89. A factor present in nuclear extracts from endothelial and nonendothelial cells binds to an AT-rich sequence located between nt −133 and −125. Mutagenesis of the AT-rich sequence interferes with nuclear protein binding and restores the activity of the −142 to +244 fragment to the level of the −89 to +244 promoter. Binding of the nuclear protein to the vWF AT-rich sequence in mobility shift assays is inhibited by competition with a consensus Oct-1 binding site and with a silencer octamer-like sequence from the vascular cell adhesion molecule-1 (VCAM-1) promoter. Subsequent supershift experiments identified Oct-1 as the transcription factor that binds to vWF and VCAM-1 silencer elements. These results indicate that Oct-1 acts as a transcriptional repressor of promoters of genes expressed in endothelial cells.© 1998 by The American Society of Hematology.

Functional assessment of von Willebrand factor expression by cancer cells of non-endothelial origin

“…Previous analyses of VWF transcriptional regulation identified a number of cis - and trans-acting factors that regulate VWF transcription. Although an endothelial-specific master regulator has not been identified, several repressors and activators that in combination participate in VWF transcription regulation have been identified [ 24 – 30 , 33 ]. In addition, distinct roles for chromatin modifications and DNA methylation were also demonstrated in VWF transcriptional regulation [ 28 , 31 , 32 ].…”

Cellular dedifferentiation of endothelium is linked to activation and silencing of certain nuclear transcription factors: implications for endothelial dysfunction and vascular biology

“…In the case of GATA-2 and c/EBP, evidence is already available for PECAM-1 gene expression to be regulated, at least in part, by these transcription factors (16,17). GATA-2 also regulates ICAM-2 (28) and endothelin gene expression (29), whereas Oct-1 was recently discovered as a silencer for CYP1A1 monooxygenases (30) and for the blood coagulating von Willebrand factor (31). Figure 8 depicts known binding sites for transcription factors in the PE-CAM-1 and CYP1A1 gene (16,27).…”

Over‐Expression of Sphingosine Kinase‐1 Enhances a Progenitor Phenotype in Human Endothelial Cells

“…To determine whether transcription factors that regulate differentiation are affected by SK-1 over-expression, we executed qRT-PCR for NANOG, OCT-1, and GATA2 [50,73,77,82]. Based on this literature, we expected to observe an increased mRNA expression of NANOG and OCT-1 and reduced expression of GATA2.…”

“…The purpose of this study was to extensively investigate whether SK-1 over-expression in human ECs could de-differentiate these cells to attain a progenitor phenotype and function, as well as identify potential transcription factors involved in this process. To determine this, we analyzed whether SK-1 over-expression in HUVEC altered mRNA and protein expression of various known EC ⁄ EPC surface markers, functional capacity of the cells as well as mRNA expression of NANOG, OCT-1, and GATA2, transcription factors associated with a progenitor phenotype [50,73,77,82]. To achieve SK-1 over-expression in human ECs, we transduced HUVEC with lentivirus containing SK-1 cDNA.…”