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 (trăns-ăk′tə-vāt′, trănz-)
tr.v. trans·ac·ti·vat·ed, trans·ac·ti·vat·ing, trans·ac·ti·vates
To stimulate the transcription of (a gene in a host cell) by binding to DNA. Genes can be transactivated naturally by a virus or cellular protein or artificially by the insertion of a transactivator gene and segment of DNA into a cell.

trans′ac·ti·va′tion n.
trans·ac′ti·va′tor n.
References in periodicals archive ?
Chimeric proteins consisting of the DNA binding domain of the yeast transcription factor Gal4 and the ER[alpha] or ER[beta] hormone binding domain, which were transiently transfected in SkBr3 cells, showed a strong transactivation by E2 but not by atrazine (Figure 1E,F), confirming that atrazine did not transactivate ER.
Estrogens may bind to two types of receptors in target cells: estrogen receptor-alpha (ER-alpha) and ER-beta, both of which can transactivate gene expression in target cells.
RAF inhibitors transactivate RAF dimers and ERK signalling in cells with wild-type BRAF.
Transcription factors PPAR gamma and C/EBP have been shown to transactivate some of the adipocyte-expressed genes.
Concerns that subsequently arose regarding a potential adverse impact on breast cancer risk and the growth of existing estrogen dependent tumours were predominantly triggered by findings from in vitro research as well as rodent studies showing that isoflavones bind to and transactivate estrogen receptors (ERs) (Jefferson 2000, Muthyala 2004) and induce proliferation and estrogenic markers in MCF-7 cells (an ER positive breast cancer cell line) (Bodinet 2004, Ju 2001, Schmidt 2001).
The authors suggest that abnormalities of proliferation regulation in endometrial tumors may be connected with accumulation of mutant p53 protein, its disability to transactivate such target genes as p21, with changes in expression of p16 protein.
Notably, the proinflammatory transcription factor NF-[kappa]B has been shown to transactivate lipocalin-2 expression through binding with a consensus motif in the promoter region of the lipocalin-2 gene (18), suggesting that this secretory protein might be involved in the inflammatory responses.
ATM targets p53 protein, a transcription factor that can bind to specific DNA sequences and transactivate certain p53-responsive genes while DNA-PK targets mdm2.
Both Epstein-Barr viral nuclear antigen 2 (EBNA-2) and activated Notch1 transactivate genes by interacting with the cellular protein RBP-J kappa.
PPAR-[gamma]2 is known as a master regulator of adipogenesis because of its ability to transactivate adipogenic target genes such as aP2, GLUT4, fatty acid synthase, LPL, acetyl-CoA carboxylase, and steroyl-CoA desaturase (van Bilsen et al.
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