The senescence marker protein (SMP-2) of the rat liver: purification, immunochemical characterization and age-dependent regulation

Bandana Chatterjee, Michael A. Mancini, Arun K. Roy

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

In vitro translation of total rat hepatic mRNAs has identified a 31 kilodalton senescence marker protein (SMP-2) which is present in higher amounts in prepubertal and senescent males than in the post-pubertal adult male (more than 10-fold). SMP-2 is an androgen-repressible protein. The negative regulation of the SMP-2 gene activity by androgen accounts for its increased expression during the androgen insensitive states of the prepubertal and senescent livers, and its constitutive expresion in the female liver. A combination of separation procedures including salt fractionation, chromatofocusing, ion-exchange chromatography and preparative gel electrophoresis have led to the purification of SMP-2 to apparent homogeneity. The purified protein showed the same electrophoretic mobility as the sex- and age-specific in vitro translation product of hepatic mRNAs. The polyclonal antibody to SMP-2 was produced in the rabbit. The antibody selectively reacted with the 31 kDa sex- and age-specific translation product of hepatic mRNAs. Western blot analysis of the liver cytosol confirms monospecificity of the antiserum, as well as age- and sex-dependent changes in the tissue level of SMP-2. Histochemical staining of liver sections with the antiserum reveals a preferential periportal localization of SMP-2 in the hepatocytes. This finding is in marked contrast to the androgen-inducible α2u glubulin which is preferentially synthesized and localized in the pericentral hepatocytes. Thus, the zonal distribution of SMP-2 correlates with polarized androgen sensitivity of the hepatocytes witin the liver lobule.

Original languageEnglish (US)
Pages (from-to)162-169
Number of pages8
JournalBBA - General Subjects
Volume1034
Issue number2
DOIs
StatePublished - May 16 1990

Keywords

  • (Rat liver)
  • Aging
  • Androgen action
  • Immunocytochemistry
  • Lobular zonation
  • Protein purification

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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