Jf. Baskar et al., THE ENHANCER DOMAIN OF THE HUMAN CYTOMEGALOVIRUS MAJOR IMMEDIATE-EARLY PROMOTER DETERMINES CELL-TYPE-SPECIFIC EXPRESSION IN TRANSGENIC MICE, Journal of virology, 70(5), 1996, pp. 3207-3214
The human cytomegalovirus (HCMV) major immediate-early promoter (MIEP)
is one of the first promoters to activate upon infection. To examine
HCMV MIEP tissue-specific expression, transgenic mice were established
containing the lacZ gene regulated by the MIEP (nucleotides -670 to 54). In the transgenic mice, lacZ expression was demonstrated in 19 of
29 tissues tested by histochemical and immunochemical analyses. These
tissues included brain, eye, spinal cord, esophagus, stomach, pancrea
s, kidney, bladder, testis, ovary, spleen, salivary gland, thymus, bon
e marrow, skin, cartilage, and cardiac, striated and smooth muscles. A
lthough expression was observed in multiple organs, promoter activity
was restricted to specific cell types. The cell types which demonstrat
ed HCMV MIEP expression included retinal cells of the eye, ductile cel
ls of the salivary gland, exocrine cells of the pancreas, mucosal cell
s of the stomach and intestine, neuronal cells of the brain, muscle fi
bers, thecal cells of the-corpus luteum, and Leydig and sperm cells of
the testis. These observations indicate that the HCMV MIEP is not a p
an-specific promoter and that the majority of expressing tissues corre
late with tissues naturally infected by the virus in the human host.