AN OCTAMER ELEMENT FUNCTIONS AS A REGULATORY ELEMENT IN THE DIFFERENTIATION-RESPONSIVE CD11C INTEGRIN GENE PROMOTER - OCT-2 INDUCIBILITY DURING MYELOMONOCYTIC DIFFERENTIATION
C. Lopezrodriguez et al., AN OCTAMER ELEMENT FUNCTIONS AS A REGULATORY ELEMENT IN THE DIFFERENTIATION-RESPONSIVE CD11C INTEGRIN GENE PROMOTER - OCT-2 INDUCIBILITY DURING MYELOMONOCYTIC DIFFERENTIATION, The Journal of immunology, 158(12), 1997, pp. 5833-5840
The integrin CD11c/CD18 mediates leukocyte adhesion to endothelium and
other cell types and is a receptor for LPS, iC3b, and fibrinogen, CD1
1c expression is restricted to myeloid and activated B cells, is regul
ated during leukocyte differentiation, and constitutes a diagnostic to
ol for hairy cell leukemia. Mapping of in vivo DNA-protein interaction
s in the CD11c proximal promoter revealed three adjacent myeloid-speci
fic interactions, one of which lies on an octamer consensus sequence,
ATTT GCAT (Oct185), Oct185 disruption increased the CD11c promoter act
ivity while decreasing its myeloid differentiation responsiveness, ind
icating that Oct185 contributes to the activity of the CD11c promoter
and suggesting that Oct185 is a negative regulatory element whose func
tion changes during myeloid differentiation, Oct185 is recognized by t
he ubiquitous Oct-1 factor in all cell lineages and by Oct-2 in B lymp
hoid lineage cells, Unexpectedly, Oct-2 binding to Oct185 was induced
de novo upon monocytic differentiation of U937 and HL-60 cells but not
during HL-60 granulocytic differentiation, as determined by electroph
oretic mobility shift assays and immunochemical studies, and Oct-2 com
plexes were also observed in cultured adherent monocytes, Western blot
ting showed that the pattern of Oct-2 isoforms in myeloid cells is sim
ilar to that seen in B cells, The Oct-2 up-regulated expression in dif
ferentiating myeloid cells and its binding to the Oct185 negative regu
latory element suggests its involvement in the differentiation-regulat
ed activity of the CD11c promoter and might represent an important par
ameter for the myeloid- and B cell-restricted expression of the CD11c/
CD18 integrin and other molecules with similar patterns of expression.