The human ITGB4BP gene is constitutively expressed in vitro, but highly modulated in vivo

Alessandra Donadini, Alessandra Giodini, Francesca Sanvito, Pier Carlo Marchisio, Stefano Biffo

Research output: Contribution to journalArticle

Abstract

The ITGB4BP gene encodes for a highly conserved protein, named p27 BBP (also known as eIF6), originally identified in mammals as a cytoplasmic interactor of β4 integrin. In vitro and in vivo studies demonstrated that p27 BBP is essential for cell viability and has a primary function in the biogenesis of the 60S ribosomal subunit. Here we report the genomic organization of the human ITGB4BP gene and show that its gene product is expressed with features of a housekeeping element in vitro, but is regulated in a cell specific fashion in vivo. The human gene spans 10 kb and comprises seven exons and six introns. The 5′ flanking region shows a TATA-less promoter, canonical CpG islands, and binding sites for serum responsive elements. In cultured cells, p27 BBP mRNA and protein are constitutively expressed and stable. A gradual loss of p27 BBP mRNA can be observed only after prolonged serum starvation, and heat shock treatment. In contrast, p27 BBP mRNA and protein levels in vivo are variable among different organs. More strikingly, immunohistochemical analysis shows that the p27 BBP protein is present in a cell specific fashion, even within the same tissue. Taken together, these data show that ITGB4BP gene expression is highly regulated in vivo, possibly by the combination of tissue specific factors and protein synthesis pathways.

Original languageEnglish
Pages (from-to)35-43
Number of pages9
JournalGene
Volume266
Issue number1-2
DOIs
Publication statusPublished - Mar 21 2001

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Keywords

  • 60S subunit
  • Genomic structure
  • Nucleolus
  • P27
  • SnoRNA

ASJC Scopus subject areas

  • Genetics

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