TY - JOUR
T1 - The human ITGB4BP gene is constitutively expressed in vitro, but highly modulated in vivo
AU - Donadini, Alessandra
AU - Giodini, Alessandra
AU - Sanvito, Francesca
AU - Marchisio, Pier Carlo
AU - Biffo, Stefano
N1 - Funding Information:
We thank Dr Marcello Ceci for his help in the snoRNA analysis; Dr Sarah Pozzi for the support in the sequencing facility; the YAC Screening Centre Telethon for providing the PAC library for the screening; Dr Giovanni Lavorgna for the help in the promoter analysis and Dr Stefano Belgeri who provided the β-actin probe. This work was supported by DEBRA 98-01 (SB, AD), Telethon E712 (SB), AIRC and MURST (PCM).
PY - 2001/3/21
Y1 - 2001/3/21
N2 - The ITGB4BP gene encodes for a highly conserved protein, named p27BBP (also known as eIF6), originally identified in mammals as a cytoplasmic interactor of β4 integrin. In vitro and in vivo studies demonstrated that p27BBP 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, p27BBP mRNA and protein are constitutively expressed and stable. A gradual loss of p27BBP mRNA can be observed only after prolonged serum starvation, and heat shock treatment. In contrast, p27BBP mRNA and protein levels in vivo are variable among different organs. More strikingly, immunohistochemical analysis shows that the p27BBP 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.
AB - The ITGB4BP gene encodes for a highly conserved protein, named p27BBP (also known as eIF6), originally identified in mammals as a cytoplasmic interactor of β4 integrin. In vitro and in vivo studies demonstrated that p27BBP 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, p27BBP mRNA and protein are constitutively expressed and stable. A gradual loss of p27BBP mRNA can be observed only after prolonged serum starvation, and heat shock treatment. In contrast, p27BBP mRNA and protein levels in vivo are variable among different organs. More strikingly, immunohistochemical analysis shows that the p27BBP 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.
KW - 60S subunit
KW - Genomic structure
KW - Nucleolus
KW - P27
KW - SnoRNA
UR - http://www.scopus.com/inward/record.url?scp=0035925642&partnerID=8YFLogxK
U2 - 10.1016/S0378-1119(01)00370-5
DO - 10.1016/S0378-1119(01)00370-5
M3 - Article
SN - 0378-1119
VL - 266
SP - 35
EP - 43
JO - Gene
JF - Gene
IS - 1-2
ER -