Nonhistone protein BA is a glutathione S-transferase localized to interchromatinic regions of the cell nucleus

Bennett, C. F., Spector, D. L., Yeoman, L. C. (February 1986) Nonhistone protein BA is a glutathione S-transferase localized to interchromatinic regions of the cell nucleus. Journal of Cell Biology, 102 (2). pp. 600-9. ISSN 0021-9525

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DOI: 10.1083/jcb.102.2.600


A DNA-binding nonhistone protein, protein BA, was previously demonstrated to co-localize with U-snRNPs within discrete nuclear domains (Bennett, F. C., and L. C. Yeoman, 1985, Exp. Cell Res., 157:379-386). To further define the association of protein BA and U-snRNPs within these discrete nuclear domains, cells were fractionated in situ and the localization of the antigens determined by double-labeled immunofluorescence. Protein BA was extracted from the nucleus with the 2.0 M NaCl soluble chromatin fraction, while U-snRNPs were only partially extracted from the 2.0 M NaCl-resistant nuclear structures. U-snRNPs were extracted from the residual nuclear material by combined DNase I/RNase A digestions. Using an indirect immunoperoxidase technique and electron microscopy, protein BA was localized to interchromatinic regions of the cell nucleus. Protein BA was noted to share a number of chemical and physical properties with a family of cytoplasmic enzymes, the glutathione S-transferases. Comparison of the published amino acid composition of protein BA and glutathione S-transferases showed marked similarities. Nonhistone protein BA isolated from saline-EDTA nuclear extracts exhibited glutathione S-transferase activity with a variety of substrates. Substrate specificity and subunit analysis by SDS polyacrylamide gel electrophoresis revealed that it was a mixture of several glutathione S-transferase isoenzymes. Protein BA isolated from rat liver chromatin was shown by immunoblotting and peptide mapping techniques to be two glutathione S-transferase isoenzymes composed of the Yb and Yb' subunits. Glutathione S-transferase Yb subunits were demonstrated to be both nuclear and cytoplasmic proteins by indirect immunolocalization on rat liver cryosections. The identification of protein BA as glutathione S-transferase suggests that this family of multifunctional enzymes may play an important role in those nuclear domains containing U-snRNPs.

Item Type: Paper
Uncontrolled Keywords: Amino Acids analysis Animals Cell Compartmentation Cell Nucleus enzymology ultrastructure Chromosomal Proteins Non-Histone metabolism Electrophoresis Polyacrylamide Gel Fluorescent Antibody Technique Glutathione Transferase analysis metabolism Immunoenzyme Techniques Macromolecular Substances Microscopy Electron Molecular Weight Peptide Fragments analysis Rats Ribonucleoproteins metabolism Ribonucleoproteins Small Nuclear
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > DNA binding protein
CSHL Authors:
Communities: CSHL labs > Spector lab
Depositing User: Brian Soldo
Date: February 1986
Date Deposited: 04 Apr 2012 20:14
Last Modified: 29 Jan 2015 20:51
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