The modulation of phosphoinositidase C (PIG) beta activity upon interf
eron treatment in Burkitt lymphoma cells (Daudi) and its localization
and expression have been analyzed by Western blotting, immunocytochemi
cal and immunoelectronmicroscopy analysis. Results have disclosed an e
arly increase of phos-phatidyl-inositol-bisphosphate (PIP2) hydrolysis
at nuclear level upon interferon (IFN) treatment paralleled by the ev
idence of an increase of PIC beta 1 expression. PIC beta 1 expression
has been detected in the nuclear compartment also in a clone of Daudi
cells selected for the resistance to the antiproliferative action of i
nterferon alpha but no modulation of the enzyme has been detected upon
interferon treatment. Since no changes in terms of PIP2 hydrolysis ha
ve been found at nuclear level in this selected line, we suggest that
the antiproliferative action of interferon on Burkitt lymphoma cells i
s mediated by a possible recruitment of nuclear PIC beta 1 expression.