Antibodies to BRCA-1 and BRCA-2

BRCA-1: BRCA­1 (breast cancer 1) is a 220 kD serine phosphoprotein that has sequence homology to the granin family. BRCA­1 has a zinc binding RING finger domain at its N-terminus and putative nuclear localization signals in the central portion. The expression of BRCA­1, like a subset of granin proteins, is induced by estrogen. BRCA­1 is normally expressed in several organs, including breast and ovary. BRCA­1 mutations have been identified in a subset of breast and ovarian cancers. The subcellular localization of BRCA­1 has been described as exclusively nuclear, predominantly nuclear, nuclear in most cell types but cytoplasmic in breast and ovarian cancer cells, and as a secreted protein. The phosphorylation status and amount of BRCA­1 has been shown to be cell cycle related. It undergoes hyperphosphorylation during late G1 and S phases and is transiently dephosphorylated right after M phase. The amount of BRCA­1 is highest during S phase and continues to be relatively high through G2/M and then declines in early G1.

Applications include western blot analysis (0.2-0.4 µg/ml), and immunoprecipitation. HBL-100 human breast cells (ATCC HTB 24) are suggested as positive controls. For western blots, an extended transfer from a low percentage gel (7.5%) to the blot is necessary because the BRCA­1 protein is so large. A 4-12 hr transfer at 4°C is typically required.

BRCA-2: BRCA­2 (breast cancer 2) is a large 350-380 kD protein whose function remains to be fully elucidated. A portion of BRCA-2, encoded by exon 3 sequences at the amino terminus, has homology to the transcription factor c-Jun. The homology is in the activation domain of c-Jun, and overlaps the region of c-Jun which contains the binding site for the Jun N-terminal kinase (JNK). The sequence homology to c-Jun suggests that BRCA-2 may have a role as a transcription factor. Further, BRCA-2 exon 3 sequence (residues 18-105) can stimulate transcription in yeast and mammalian cells. Introduction of a specific mutation (tryrosine to cysteine at residue 42), inhibits the transcriptional potential of the exon 3 sequence. The tyrosine to cysteine mutation has been identified in a subset of breast cancers, suggesting that specific BRCA-2 mutations may disrupt its normal function. The transcriptional ability of exon 3 appears to be under the negative control of inhibitory regions (IR1 and IR2) located immediately on either size of exon 3. Together, IR1 and IR2 block the ability of the exon 3 sequence to stimulate transcription. Regulation by inhibitor regions has also been shown for other transcription factors. BRCA-2 binds to Rad51, a protein thought to be involved in the repair of double-stranded DNA breaks. These authors also show that BRCA-2 knockout mice undergo an early embryonic death and are hypersensitive to irradiation. The developmental arrest may be secondary to a defect in DNA repair. It is thought that BRCA-2 may be an essential cofactor in Rad51-dependent DNA repair.

Applications include western blot analysis (0.4-1 µl/ml) and immunoprecipitation ( 5 µl/ml). HBL-100 human breast cells (ATCC HTB 24) are suggested as positive controls. For western blots, an extended transfer from a low percentage gel (7.5%) to the blot is necessary because the BRCA­2 protein is so large. A 4-12 hr transfer at 4°C is typically required. In western blots, the antibodies recognize a 350-380 kD band corresponding to BRCA­2. The BRCA­2 antibodies also cross-react with smaller proteins, which may be degradation products. The cross-reacting pattern appears to be unique for each type of BRCA­2 polyclonal antibody. The identity of the cross-reacting bands has not been identified. The working concentrations are suggestions and should be optimized by the end user.

Cat. No. Description Size
66036N Affinity purified anti-human BRCA-1 (recognizes a.a. 2-20) 50 µg
66046N Affinity purified anti-human BRCA-1 (recognizes a.a. 768-793) 50 µg
66056N Affinity purified anti-human BRCA-1 (recognizes a.a. 1847-1863) 50 µg
66066E Affinity purified anti-human BRCA-2 (recognizes a.a. 1323-1346) 0.1 ml
66076E Affinity purified anti-human BRCA-2 (recognizes a.a. 2586-2600) 0.1 ml

PharMingen supplies a wide range of antibodies for cell cycle and tumor suppressor protein research, including:

For Research Use Only. Not For Diagnostic or Therapeutic Use.

[Homepage] [New Products Page] [Catalog of Products] [Ordering Information] [Technical Service]