Related Experiment Video

Updated: Aug 10, 2026

Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1
08:53

Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1

Published on: February 18, 2011

BRCA1 is a 220-kDa nuclear phosphoprotein that is expressed and phosphorylated in a cell cycle-dependent manner

Y Chen1, A A Farmer, C F Chen

  • 1Center for Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78245, USA.

Cancer Research
|July 15, 1996
PubMed

Insights

Researchers characterized mouse polyclonal antibodies against the human BRCA1 protein, identifying it as a 220-kDa nuclear phosphoprotein. BRCA1 expression and phosphorylation are cell cycle-dependent, potentially regulated by cyclin-dependent kinases.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • The human BRCA1 protein is crucial in DNA repair and tumor suppression.
  • Understanding BRCA1's expression and regulation is vital for cancer research.

Purpose of the Study:

  • To characterize mouse polyclonal antibodies against human BRCA1.
  • To investigate BRCA1 expression, phosphorylation, and cell cycle dependence.
  • To explore the role of cyclin-dependent kinases in BRCA1 regulation.

Main Methods:

  • Generation and characterization of mouse polyclonal antibodies against human BRCA1.
  • Western blot analysis using antibodies to detect BRCA1 in cell lines (HBL100).
  • In vitro translation and recombinant baculovirus expression systems for BRCA1.
  • Cell cycle analysis to determine BRCA1 expression and phosphorylation patterns.
  • Kinase assays to assess binding and phosphorylation of BRCA1 by cyclin-dependent kinases.

Main Results:

  • BRCA1 was identified as a 220-kDa nuclear phosphoprotein in normal cells.
  • Antibodies recognized both in vitro-translated and recombinant BRCA1.
  • BRCA1 expression and phosphorylation levels peaked during S and M phases of the cell cycle.
  • Cyclin-dependent kinase 2 (CDK2) and other cyclin-associated kinases (cyclins D and A) were found to bind and phosphorylate BRCA1.

Conclusions:

  • BRCA1 is a cell cycle-dependent nuclear phosphoprotein.
  • Its biological activity is likely regulated by cyclin-dependent kinases.
  • These findings provide insights into BRCA1's function and regulation in normal cells.

More Related Videos

Silencing of BRCA2 to Identify Novel BRCA2-regulated Biological Functions in Cultured Human Cells09:24

Silencing of BRCA2 to Identify Novel BRCA2-regulated Biological Functions in Cultured Human Cells

Published on: August 12, 2015

Bioluminescence Resonance Energy Transfer (BRET)-Based Assay for Measuring Interactions of CRAF with 14-3-3 Proteins in Live Cells06:44

Bioluminescence Resonance Energy Transfer (BRET)-Based Assay for Measuring Interactions of CRAF with 14-3-3 Proteins in Live Cells

Published on: March 1, 2024

Related Concept Videos

Positive Regulator Molecules01:45

Positive Regulator Molecules

To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.
Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
Positive Regulator Molecules02:39

Positive Regulator Molecules

Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
Mitogens and the Cell Cycle02:38

Mitogens and the Cell Cycle

Mitogens and their receptors play a crucial role in controlling the progression of the cell cycle. However, the loss of mitogenic control over cell division leads to tumor formation. Therefore, mitogens and mitogen receptors play an important role in cancer research. For instance, the epidermal growth factor (EGF) - a type of mitogen and its transmembrane receptor (EGFR), decides the fate of the cell's proliferation. When EGF binds to EGFR, a member of the ErbB family of tyrosine kinase...
The Ras Gene02:38

The Ras Gene

The Ras-gene-encoded proteins are regulators of signaling pathways controlling cell proliferation, differentiation, or cell survival. The Ras-gene family in humans constitutes three primary members—the HRas, NRas, and KRas. These genes code for four functionally distinct yet closely related proteins—the HRas, NRas, KRas4A, and KRas4B. The involvement of mutant Ras genes in human cancer was first discovered in 1982 and is among the most common causes of human tumorigenesis.
Ras is a superfamily...
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...