Human CD68 macrophage scavenger receptor gene 5' flanking promoter (2.9 kb)
Human CD68 gene 5' flanking promoter region (~2.9 kb) used to direct transgene expression in monocytes and macrophages. Establishes macrophage-lineage-restricted expression on its own, though high, durable expression additionally requires the CD68 first-intron (IVS-1) enhancer element included in the companion long-form construct (cd68-long).
Origin: Human CD68 gene, 2.9-kb 5' flanking promoter fragment
Characteristics
Comprises 2.9 kb of human CD68 5' flanking sequence, the proximal promoter fragment shown to direct macrophage-lineage gene expression in the RAW-264 murine macrophage cell line and in transgenic mice. Used alone, without the CD68 first-intron (IVS-1) enhancer present in the long-form construct, this fragment produces macrophage-specific but comparatively lower and more variable expression; adding the 83-bp IVS-1 intron downstream substantially increases expression level and durability.
Applications: Used to direct macrophage- and monocyte-lineage-restricted transgene expression in cell lines (e.g., RAW-264) and in transgenic or lentivirally-transduced mouse models, for studying macrophage biology and macrophage-driven disease processes.
Limitations: Without the CD68 first intron (IVS-1), this fragment alone gives lower, more variable expression than the intron-containing long-form construct (cd68-long). Lentiviral comparisons found a much shorter 150-bp proximal CD68 fragment gave greater macrophage-restricted specificity than the full 2.9-kb fragment, so promoter choice should match whether specificity or expression level is the priority.