Identification of a conserved region required for hormone dependent transcriptional activation by steroid hormone receptors.

Abstract

The oestrogen receptor stimulates transcription by means of at least two distinct transcriptional activation domains, TAF‐1 in the N‐terminal domain and TAF‐2 in the hormone binding domain. Here we show that TAF‐2 activity requires a region in the C‐terminus of the hormone binding domain between residues 538 and 552 in the mouse oestrogen receptor which is conserved among many nuclear hormone receptors. Point mutagenesis of conserved hydrophobic and charged residues significantly reduced ligand dependent transcriptional activation but had no effect on steroid or DNA binding. Mutation of the corresponding residues in the glucocorticoid receptor also abolished transcriptional activation. We therefore propose that the conserved region may be essential for ligand dependent transcriptional activation by other members of the nuclear receptor family.

Cofactor competition between the ligand-bound oestrogen receptor and an intron 1 enhancer leads to oestrogen repression of ERBB2 expression in breast cancer

“…The formation of AF2 is dependent upon the integrity and alignment across the LBD of helix 12, a C-terminal amphipathic a-helix (Danielian et al, 1992;Brzozowski et al, 1997). Abolishing AF2 activity by removal of the helix 12 sequences (residues 538 ± 552) from the active construct MOR 182 ± 599 resulted in a protein which was unable to suppress the activity of the intron 1 enhancer in our assay (Figure 4b, 182 ± 559/DH12).…”

“…All MOR expression constructs were cloned in the vector pMT2 and have been described previously (Lahooti et al, 1994) with the exception of the MOR 182 ± 599/DH12 mutant which was generated by replacing the 3' Xbal/EcoRI fragment of pMT2MOR182 ± 599 with the equivalent fragment from pJ3MORDH12 (Danielian et al, 1992). The SRC-1 expression clones were in pSG5 and all based on the SRC-1e isoform and expressed at comparable levels (Kalkhoven et al, 1998;Bevan et al, 1999).…”

The conserved nuclear receptor Ftz‐F1 is required for embryogenesis, moulting and reproduction in Caenorhabditis elegans

“…1B). Signi®cant conservation (41±47% amino acid similarity) is also found in a 15-amino acid region near the carboxyl end, corresponding to the activation domain AF-2 of some steroid receptors (Danielian et al 1992).…”

Involvement of cyclic AMP response element binding protein (CREB) and estrogen receptor phosphorylation in the synergistic activation of the estrogen receptor by estradiol and protein kinase activators

“…In the classical and most simple model of action of nuclear receptors [11], the receptor is activated by its cognate ligand [12,13] and binds to its specific hormone response element on its target genes. The magnitude of transcriptional activity is modulated by coactivator complexes [14,15] and proceeds by interaction with chromatin and the pre-initiation complex [15][16][17].…”