Human CD68 macrophage scavenger receptor promoter, short form (~660 bp)
Proximal ~660 bp fragment of the human CD68 (macrosialin) gene 5' regulatory region, active in monocytes and macrophages. Corresponds to the proximal portion of the promoter that Gough et al. (2001) combined with the CD68 first intron to drive high-level macrophage scavenger-receptor expression; this fragment alone omits that intron.
Origin: Human CD68 gene, proximal 5' promoter region only
Characteristics
Proximal ~660 bp segment of the human CD68 5' flanking region, part of the larger cassette (2.9 kb 5' flank + 83 bp first intron, IVS-1) that Gough et al. (2001) used to drive high-level, long-lasting class A scavenger-receptor expression in macrophages in vitro and in vivo. Greaves et al. (1998) showed that the CD68 first intron, not the promoter alone, is what confers macrophage-restricted specificity when placed downstream of the CD68 promoter; this short fragment does not include that intron.
Applications: Macrophage/monocyte-lineage reporter and transgene expression in transfected cell lines and cultured macrophages; suited where construct size is constrained. Not independently validated for macrophage-restricted expression in vivo — see cd68-long or cd68 for the intron-containing cassette used in transgenic mice.
Limitations: Lacks the CD68 first intron (IVS-1) that Greaves et al. (1998) identified as required for macrophage-restricted specificity, so expression in non-macrophage cells is more likely than with the full cassette; strength and specificity in vivo are expected to be weaker than the intron-containing cd68/cd68-long constructs, which have not been directly tested for this exact fragment.