Characterization of the human gene encoding the scavenger receptor expressed by endothelial cell and its regulation by a novel transcription factor, endothelial zinc finger protein-2.
The scavenger receptor expressed by endothelial cell (SREC), mediates the selective uptake of modified low density lipoprotein (LDL), such as acetylated LDL and oxidized LDL, into endothelial cells. The SREC gene spans 12 kilobase pairs and contains 11 exons. Analysis of full-length cDNA clones of SREC from a peripheral blood leukocyte cDNA library revealed that at least five alternatively spliced cDNAs were present, and two of them encoded soluble forms of SREC. The transcription start site of the SREC gene was mapped, and DNA sequence analysis revealed an Sp1 binding site in its proximal region. Deletion analysis of the 5'-flanking sequence revealed that sequence between base pairs -108 and -98 was critical for the promoter activity. This region contained half of an inverted repeat (IR) sequence with a triple nucleotide spacer (IR-3). A protected sequence between base pairs -268 and +17 was defined by in vitro DNase I footprinting analysis using human umbilical vein endothelial cell (HUVEC) nuclear extract. A novel transcription factor, endothelial zinc finger protein-2 (EZF-2), that binds to the 5'-flanking critical region of the SREC promoter activity was cloned from a HUVEC cDNA library employing a one-hybrid system. Whereas purified recombinant Sp1 alone produced similar protection in in vitro DNase I footprinting analysis, EZF-2 also bound to the 5'-flanking region SREC promoter. Co-transfection of SREC promoter and Sp1 or EZF-2 expression plasmids in HUVEC revealed that EZF-2 but not Sp1 increased SREC promoter activity. On the other hand, the mutation of either the Sp1 motif or IR-3 motif resulted in a decrease in the promoter activity. These results suggest that whereas Sp1 is the major nuclear protein bound to the regulatory region of the promoter, both EZF-2 and Sp1 are responsible for its regulation.
Adachi
Hideki
H
Laboratory of Cellular Biochemistry, RIKEN (The Institute of Physical and Chemical Research), Saitama 351-0198, Japan. adachih@postman.riken.go.jp
Tsujimoto
Masafumi
M
D000595:Amino Acid Sequence; D015703:Antigens, CD / Q000235:genetics; D018955:CD36 Antigens / Q000235:genetics; D018983:DNA Footprinting; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003850:Deoxyribonuclease I; D004730:Endothelium, Vascular / Q000378:metabolism*; D005091:Exons; D005786:Gene Expression Regulation / Q000502:physiology*; D017930:Genes, Reporter; D015698:Genomic Library; D006801:Humans; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D008077:Lipoproteins, LDL / Q000378:metabolism; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010957:Plasmids; D011971:Receptors, Immunologic / Q000235:genetics* / Q000502:physiology; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D015183:Restriction Mapping; D051122:Scavenger Receptors, Class B; D051128:Scavenger Receptors, Class F; D014157:Transcription Factors / Q000378:metabolism*; D016335:Zinc Fingers
D015703:Antigens, CD; D018955:CD36 Antigens; D017931:DNA Primers; D004268:DNA-Binding Proteins; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D008077:Lipoproteins, LDL; D008565:Membrane Proteins; D011971:Receptors, Immunologic; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C495126:SCARF1 protein, human; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B; D051128:Scavenger Receptors, Class F; D014157:Transcription Factors; C431793:ZNF71 protein, human; D003850:Deoxyribonuclease I