R. Hayashi et al., THE PU.1 BINDING-SITE IS A CIS-ELEMENT THAT REGULATES PRO-B PRE-B SPECIFICITY OF V-KAPPA-J-KAPPA JOINING/, The Journal of immunology, 159(9), 1997, pp. 4145-4149
We have previously shown that the PU.1 binding motif (GAG CAA) in the
3'-enhancer region in the Ig kappa gene is responsible for the negativ
e regulation of tissue (B/T)-specific V kappa-J kappa joining, Here we
report that the PU.1 binding site also regulates the stage (pro-B/pre
-B) specificity of V kappa-J kappa joining, In the substrate with base
substitutions in the PU.1 binding motif, recombination took place in
bath pro-B (B220(dull)/CD43(+)) and pre-B (B220(dull)/CD43(-)) cells,
In the transcriptional regulation, the PU.1 motif acts in a positive m
anner cooperatively with the nuclear factor-EMS (or PIP) motif (GAAAAC
), which is located 2 bp downstream from the PU.1 motif, Interestingly
, base substitutions in the nuclear factor EM5 (PIP) motif did not aff
ect the pro-B/pre-B specificity of V kappa-J kappa joining. Thus, the
PU.1 motif regulates both temporal and tissue-specific rearrangements,
while nuclear factor-EMS is not involved in the regulation of Ig kapp
a recombination.