The RB-related gene Rb2/p130 in neuroblastoma differentiation and in B-myb promoter down-regulation.
The retinoblastoma family of nuclear factors is composed of RB, the prototype of the tumour suppressor genes and of the strictly related genes p107 and Rb2/p130. The three genes code for proteins, namely pRb, p107 and pRb2/p130, that share similar structures and functions. These proteins are expressed, often simultaneously, in many cell types and are involved in the regulation of proliferation and differentiation. We determined the expression and the phosphorylation of the RB family gene products during the DMSO-induced differentiation of the N1E-115 murine neuroblastoma cells. In this system, pRb2/p130 was strongly up-regulated during mid-late differentiation stages, while, on the contrary, pRb and p107 resulted markedly decreased at late stages. Differentiating N1E-115 cells also showed a progressive decrease in B-myb levels, a proliferation-related protein whose constitutive expression inhibits neuronal differentiation. Transfection of each of the RB family genes in these cells was able, at different degrees, to induce neuronal differentiation, to inhibit [3H]thymidine incorporation and to down-regulate the activity of the B-myb promoter.
Raschellà
G
G
Section of Toxicology and Biomedical Sciences, Ente Nuove Tecnologie Energia e Ambiente (ENEA) Via Anguillarese 301, 00060 Rome, Italy.
Tanno
B
B
Bonetto
F
F
Negroni
A
A
Claudio
P P
PP
Baldi
A
A
Amendola
R
R
Calabretta
B
B
Giordano
A
A
Paggi
M G
MG
D000818:Animals; D018797:Cell Cycle Proteins; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D015536:Down-Regulation; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D051379:Mice; D009363:Neoplasm Proteins / Q000378:metabolism; D009447:Neuroblastoma / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics; D010750:Phosphoproteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011506:Proteins; D016160:Retinoblastoma Protein / Q000235:genetics; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D015534:Trans-Activators / Q000235:genetics*; D014162:Transfection; D014407:Tumor Cells, Cultured
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C499306:Mybl2 protein, mouse; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011506:Proteins; C489485:Rbl1 protein, mouse; C493838:Rbl2 protein, mouse; D016160:Retinoblastoma Protein; D050720:Retinoblastoma-Like Protein p107; D050717:Retinoblastoma-Like Protein p130; D015534:Trans-Activators; D004121:Dimethyl Sulfoxide