title: Nuclear localization and binding affinity of STAT5b for the alpha(2)-macroglobulin gene promoter during rat liver development and the acute-phase response.
abstract: Expression of the rat alpha(2)-macroglobulin (MG) gene undergoes dynamic changes throughout an individual's life and during the acute-phase (AP) response. Details of the participation of the STAT family of transcription factors in its control remain incompletely understood. Here we examined the involvement of STAT5b in MG gene expression during development and the AP response. Immuno-blot analysis revealed the highest nuclear level of STAT5b in the fetus and during postnatal development, whereas in the adult it decreased. Stimulation of MG expression during the AP response was accompanied by a decrease in STAT5b. Examination of STAT5b localization revealed that the relative concentrations of STAT5b were higher in the nuclear matrix than in the nuclear extract. Affinity chromatography with the extended promoter region of the MG gene (-825/+12), followed by immuno-blot analysis, revealed dynamic changes in STAT5b binding. The highest concentration of the promoter-binding form of STAT5b was observed in the fetus. As postnatal development progressed, the level of promoter-bound STAT5b decreased and in the adult liver it was the lowest. Stimulation of MG gene expression during the AP response in both the fetus and adult was accompanied by significantly decreased STAT5b binding to the MG promoter. The AP response was accompanied by lower levels of STAT5b serine and tyrosine phosphorylation in both fetus and adult. In the nuclear matrix derived from adult tissues, tyrosine phosphorylated species were completely absent. We conclude that developmental-stage differences in the mechanisms that determine STAT5b nuclear localization contribute to its activity in vivo.
authors.affiliation: Department of Molecular Biology, Institute for Biological Research, Belgrade, Serbia. mista@ibiss.bg.ac.yu
authors.forename: Mirjana
authors.initials: M
authors.lastname: Mihailović
authors.forename: Svetlana
authors.initials: S
authors.lastname: Dinić
authors.forename: Desanka
authors.initials: D
authors.lastname: Bogojević
authors.forename: Svetlana
authors.initials: S
authors.lastname: Ivanović-Matić
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Uskoković
authors.forename: Jelena
authors.initials: J
authors.lastname: Arambasić
authors.forename: Ilijana
authors.initials: I
authors.lastname: Grigorov
authors.forename: Nevena
authors.initials: N
authors.lastname: Grdović
authors.forename: Melita
authors.initials: M
authors.lastname: Vidaković
authors.forename: Vesna
authors.initials: V
authors.lastname: Martinović
authors.forename: Miodrag
authors.initials: M
authors.lastname: Petrović
authors.forename: Goran
authors.initials: G
authors.lastname: Poznanović
mesh_terms: D000210:Acute-Phase Reaction; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D007700:Kinetics; D008099:Liver / Q000254:growth & development / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D000511:alpha-Macroglobulins / Q000235:genetics* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D050799:STAT5 Transcription Factor; C494097:Stat5b protein, rat; D000511:alpha-Macroglobulins; D004247:DNA