Localization of BRCA1 and a splice variant identifies the nuclear localization signal

Inherited mutations in BRCA1 confer susceptibility to breast and ovarian neoplasms. However, the function of BRCA1 and the role of BRCA1 in noninherited cancer remain unknown. Characterization of alternately spliced forms of BRCA1 may identify functional regions; thus, we constructed expression vectors of BRCA1 and a splice variant lacking exon 11, designated BRCA1 delta 672-4095. Immunofluorescence studies indicate nuclear localization of BRCA1 but cytoplasmic localization of BRCA1 delta 672-4095. Two putative nuclear localization signals (designated NLS1 and NLS2) were identified in exon 11; immunofluorescence studies indicate that only NLS1 is required for nuclear localization. RNA analysis indicates the expression of multiple, tissue-specific forms of BRCA1 RNAs; protein analysis with multiple antibodies suggests that at least three BRCA1 isoforms are expressed, including those lacking exon 11. The results suggest that BRCA1 is a nuclear protein and raise the possibility that splicing is one form of regulation of BRCA1 function by alteration of the subcellular localization of expressed proteins.

[1]  C. Osborne,et al.  Location of BRCA1 in Human Breast and Ovarian Cancer Cells , 1996, Science.

[2]  M. King,et al.  Growth retardation and tumour inhibition by BRCA1 , 1996, Nature Genetics.

[3]  M. Ahmad,et al.  Antisense RNA to the putative tumor suppressor gene BRCA1 transforms mouse fibroblasts. , 1996, Oncogene.

[4]  G. Blobel,et al.  Protein import into nuclei: association and dissociation reactions involving transport substrate, transport factors, and nucleoporins , 1995, Cell.

[5]  B. Weber,et al.  Mouse Brca1: localization sequence analysis and identification of evolutionarily conserved domains. , 1995, Human molecular genetics.

[6]  A. Bradley,et al.  Murine Brca1: sequence and significance for human missense mutations. , 1995, Human molecular genetics.

[7]  C. Osborne,et al.  Aberrant Subcellular Localization of BRCA1 in Breast Cancer , 1995, Science.

[8]  H. Nguyen,et al.  Hormone-dependent regulation of BRCA1 in human breast cancer cells. , 1995, Cancer research.

[9]  L. Bennett,et al.  Isolation of the mouse homologue of BRCA1 and genetic mapping to mouse chromosome 11. , 1995, Genomics.

[10]  Junzhe Xu,et al.  The developmental pattern of Brca1 expression implies a role in differentiation of the breast and other tissues , 1995, Nature Genetics.

[11]  David L. Page,et al.  Decreased expression of BRCA1 accelerates growth and is often present during sporadic breast cancer progression , 1995, Nature Genetics.

[12]  Francis S. Collins,et al.  Mutations in the BRCA1 gene in families with early-onset breast and ovarian cancer , 1994, Nature Genetics.

[13]  Steven E. Bayer,et al.  A strong candidate for the breast and ovarian cancer susceptibility gene BRCA1. , 1994, Science.

[14]  M. Skolnick,et al.  BRCA1 mutations in primary breast and ovarian carcinomas. , 1994, Science.

[15]  D. Easton,et al.  Genetic linkage analysis in familial breast and ovarian cancer: results from 214 families. The Breast Cancer Linkage Consortium. , 1993, American journal of human genetics.

[16]  L. Su,et al.  TFE3: a helix-loop-helix protein that activates transcription through the immunoglobulin enhancer muE3 motif. , 1990, Genes & development.

[17]  H. Temin,et al.  Transactivation of gene expression by nuclear and cytoplasmic rel proteins , 1989, Molecular and cellular biology.

[18]  D. Klessig,et al.  Nuclear localization of the adenovirus DNA-binding protein: requirement for two signals and complementation during viral infection , 1989, Molecular and cellular biology.

[19]  N. Jones,et al.  A karyophilic signal sequence in adenovirus type 5 E1A is functional in Xenopus oocytes but not in somatic cells , 1989, Journal of virology.

[20]  D. Baltimore,et al.  The mouse type IV c-abl gene product is a nuclear protein, and activation of transforming ability is associated with cytoplasmic localization , 1989, Cell.

[21]  L. Su,et al.  Identification and characterization of two functional domains within the murine heavy-chain enhancer , 1988, Molecular and cellular biology.

[22]  W. Richardson,et al.  Sequence requirements for nuclear location of simian virus 40 large-T antigen , 1984, Nature.

[23]  A. Feinberg,et al.  A technique for radiolabeling DNA restriction endonuclease fragments to high specific activity. , 1983, Analytical biochemistry.

[24]  A. van der Eb,et al.  A new technique for the assay of infectivity of human adenovirus 5 DNA. , 1973, Virology.

[25]  F. Couch,et al.  Mutations and Polymorphisms in the familial early‐onset breast cancer (BRCA1) gene , 1996, Human mutation.

[26]  T. Boulikas,et al.  Nuclear localization signals (NLS). , 1993, Critical reviews in eukaryotic gene expression.

[27]  P. Freemont.  The RING finger. A novel protein sequence motif related to the zinc finger. , 1993, Annals of the New York Academy of Sciences.