Growth factor‐induced promoter activation of murine phospholipase C δ4 gene

Abstract

Phospholipase C d4 (PLCd4) is one of the delta-type PLC isozymes, the expression of which is induced in nuclei by treatment with serum and also in some cancer cells. We isolated and analyzed a promoter region of the murine PLCd4 gene. DNA sequence analysis showed that this region is GC-rich and has no TATA box, and the region from 2143 to 2127 was found, by luciferase activity and gel mobility-shift assay, to be essential for transcription of PLCd4. We also found that the promoter activity of PLCd4 was stimulated by treatment with growth factors such as bradykinin, lysophosphatidic acid, and Ca 21 ionophore in addition to serum. In parallel, we detected PLCd4 mRNA induction and an increase in complex formation of the promoter region and nuclear protein from HeLa cells on stimulation with these growth factors. Finally, we found that trapping the growth factor-induced cytoplasmic Ca 21 -inhibited activation of the promoter activity and protein induction in nuclei. These results show that PLCd4 may have an important role in nuclei in response to growth factors, and its expression may be partially regulated by an increase in cytoplasmic Ca 21.

Translocation of N-WASP by Nuclear Localization and Export Signals into the Nucleus Modulates Expression of HSP90

“…Gel-mobility Shift Assay-Nuclear fractions for gel shift assays was prepared as described previously (24). The sequence of the probe was the same as that used in luciferase reporter plasmid.…”

Lipids and signal transduction in the nucleus.

“…Nu clei of NIH 3T3 cells con tained all four isozymes of the b-fam ily of PI-PLC [20]. PLC g-isoforms, which are ac ti vated by ty ro sine kin ases, Tau pro tein, arachidonic acid or phos pha tid ic acid, and PLC isoform d, with an un known mech a nism of ac ti va tion, were also de tected in the nu cleus [3, 5, 21,22].…”

Downregulation of Phospholipase C δ3 by cAMP and Calcium

“…By luciferase assay, A23187 increased the promoter activity twofold at 2 M concentration in Hela cells (55). However, PLC␦3 mRNA expression was downregulated by A23187 treatment.…”