Sa. Omori et al., DIFFERENTIAL INTERACTION OF NUCLEAR FACTORS WITH THE LEUKOCYTE-SPECIFIC PP52 PROMOTER IN B-CELL AND T-CELL, The Journal of immunology, 159(4), 1997, pp. 1800-1808
The leukocyte-specific, cytoskeleton-binding pp52 (LSP-1, WP-34) prote
in is widely expressed in multiple leukocyte lineages, including B and
T lymphocytes, granulocytes, and macrophages. We previously detected
a tissue specific promoter preceding the exon encoding the N terminus
of the pp52 leukocyte protein, Here we describe the functional charact
erization of this promoter and identification of the factors in B and
T cells that regulate its activity, The pp52 promoter contains an init
iator specifying the unique 5' terminus of pp52 mRNA, tandem pairs of
Ets and SP1 motifs, and a lone C/EBP motif, All these motifs are essen
tial and collectively control transcriptional activity, DNA binding st
udies and Ab supershift assays revealed that different combinations of
factors interact with these motifs in B tells vs T cells, The Ets mot
ifs are preferentially bound by PU-1 in B cell extracts from all stage
s of development, whereas a different Ets family member reacts with th
ese motifs in T cell extracts, The C/EBP motif is bound by Ig/EBP-1 in
pre-B cell and T cell extracts, but is replaced by nuclear factor-IL-
6 beta or a nuclear factor-IL-6 beta-Ig/EBP-1 heterodimer in plasmacyt
oma cell extracts, Despite its reported role as a negative regulator o
f transcription, Ig/EBP-1 appears to exert a stimulatory effect on thi
s promoter, These findings reveal the Features controlling the pp52 pr
omoter in B and T cells and provide the foundation for determining the
regulation of this promoter in other leukocyte lineages.