E. Kutoh et al., Cell-density (cycle) dependent silencer of the rat insulin-like growth factor binding protein-2 (IGFBB-2) gene, GROW FACTOR, 16(3), 1999, pp. 217-223
An element,which has a negative effect on transcription has been identified
in the 5'-flanking region of the rat insulin-like growth factor binding pr
otein-2 (IGFBP-2) gene. This element was confirmed to be a silencer by trun
cation or by linking it to a heterologous promoter. The silencer activity d
isappeared in the growth-arrested BRL-3A cells at the G1/S border by high c
ell density where the IGFBP-2 production is highly elevated. This observati
on may represent a novel mechanism through which gene expression is control
led by modulation of a silencer. Taken together, these results suggest a re
gulatory link between cell growth and IGFBP-2 expression regulated by its s
ilencer.