MilliporeSigma
  • Home
  • Search Results
  • The expression of B23 and EGR1 proteins is functionally linked in tumor cells under stress conditions.

The expression of B23 and EGR1 proteins is functionally linked in tumor cells under stress conditions.

BMC cell biology (2015-11-19)
Donatella Ponti, Daniela Bastianelli, Paolo Rosa, Luca Pacini, Mohsen Ibrahim, Erino Angelo Rendina, Giuseppe Ragona, Antonella Calogero
ABSTRACT

The nucleolus is a multi-domain enriched with proteins involved in ribosome biogenesis, cell cycle and apoptosis control, viral replication and differentiation of stem cells. Several authors have suggested a role for the nucleolus also in malignant transformation. We have recently demonstrated that under specific circumstances the transcriptional factor EGR1 is shuttled to the nucleolus where it functions as a negative regulator of RNA polymerase I. Since this activity is hampered in ARF -/- cells, and ARF transcription is regulated by EGR1 while the turnover of ARF protein is under the control of B23, we speculated that some sort of cooperation between EGR1 and B23 might also exist. In this work we identified a canonical EGR1 binding site on the B23 promoter through experiments of transactivation and in vitro DNA binding assay. We then found that the levels of B23 expression are directly correlated with those of EGR1, and that this correlation applies to several cellular types and to different stress conditions. Furthermore, we showed that EGR1 stability and accumulation within the nucleolus is in turn regulated by B23 through proteasome involvement, similarly to ARF turnover. Our results highlight EGR1 as a regulator of B23 expression actively playing within the newly discovered nucleolar B23-ARF-EGR1 network.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Sodium deoxycholate, BioXtra, ≥98.0% (dry matter, NT)
Sigma-Aldrich
Magnesium chloride, powder, <200 μm
Sigma-Aldrich
Sodium deoxycholate, ≥97% (titration)
Sigma-Aldrich
Acrylamide solution, 40%, suitable for electrophoresis, sterile-filtered
Sigma-Aldrich
Magnesium chloride, BioReagent, suitable for insect cell culture, ≥97.0%
Sigma-Aldrich
Magnesium chloride, anhydrous, ≥98%
Sigma-Aldrich
Magnesium chloride, AnhydroBeads, −10 mesh, 99.99% trace metals basis
Sigma-Aldrich
Magnesium chloride, AnhydroBeads, −10 mesh, 99.9% trace metals basis
SAFC
Sodium deoxycholate
Sigma-Aldrich
Magnesium chloride solution, 0.1 M
Sigma-Aldrich
Acrylamide, suitable for electrophoresis, ≥99% (HPLC), powder
Sigma-Aldrich
Magnesium chloride solution, BioUltra, for molecular biology, ~0.025 M in H2O
Sigma-Aldrich
Magnesium chloride solution, BioUltra, for molecular biology, 2 M in H2O
Sigma-Aldrich
Phenylmethanesulfonyl fluoride, ≥99.0% (T)
Sigma-Aldrich
Magnesium chloride solution, for molecular biology, 1.00 M±0.01 M
Sigma-Aldrich
Magnesium chloride solution, PCR Reagent, 25 mM MgCI2 solution for PCR
Sigma-Aldrich
Acrylamide, for molecular biology, ≥99% (HPLC)
Sigma-Aldrich
Actinomycin D, from Streptomyces sp., suitable for cell culture, ≥95%
Sigma-Aldrich
Magnesium chloride solution, BioUltra, for molecular biology, ~1 M in H2O
Sigma-Aldrich
Acrylamide, suitable for electrophoresis, ≥99%
Sigma-Aldrich
Actinomycin D, from Streptomyces sp., ≥95% (HPLC)
Sigma-Aldrich
Actinomycin D, from Streptomyces sp., ~98% (HPLC)
Sigma-Aldrich
Phenylmethanesulfonyl fluoride, ≥98.5% (GC)