Biomedical subjects

Elaine R Vickers

Publications and source records attributed to Elaine R Vickers.

2 recordsLinked to original sources

PubMed2004

Ternary complex factor-serum response factor complex-regulated gene activity is required for cellular proliferation and inhibition of apoptotic cell death.

Members of the ternary complex factor (TCF) subfamily of the ETS-domain transcription factors are activated through phosphorylation by mitogen-activated protein kinases (MAPKs) in response to a variety of mitogenic and stress stimuli. The TCFs bind and activate serum response elements (SREs) in the promoters of target genes in a ternary complex with a second transcription factor, serum response factor (SRF). The association of TCFs with SREs within immediate-early gene promoters is suggestive of a role for the ternary TCF-SRF complex in promoting cell cycle entry and proliferation in response to mitogenic signaling. Here we have investigated the downstream gene regulatory and phenotypic effects of inhibiting the activity of genes regulated by TCFs by expressing a dominantly acting repressive form of the TCF, Elk-1. Inhibition of ternary complex activity leads to the downregulation of several immediate-early genes. Furthermore, blocking TCF-mediated gene expression leads to growth arrest and triggers apoptosis. By using mutant Elk-1 alleles, we demonstrated that these effects are via an SRF-dependent mechanism. The antiapoptotic gene Mcl-1 is identified as a key target for the TCF-SRF complex in this system. Thus, our data confirm a role for TCF-SRF-regulated gene activity in regulating proliferation and provide further evidence to indicate a role in protecting cells from apoptotic cell death.

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PubMed2002

The use of inducible engrailed fusion proteins to study the cellular functions of eukaryotic transcription factors.

Transcription factors determine cell lineages, control cell fate, and regulate cellular responses to stimuli. Many methods are currently used to study the function of transcription factors in a cellular context and several of these involve overexpressing a constitutively active form of the protein and studying its effects. Here we outline an alternative approach involving the inducible expression of dominant-negative transcription factors in human cell lines. Dominant-negative transcription factors can be used to investigate the effect of signaling pathways on complex cellular processes that are regulated by a particular transcription factor. Potent dominant-negative transcription factors can be created by using fusions to the engrailed repressor domain. These fusion proteins can be coupled to inducible expression systems such as the ecdysone-inducible system. The ability to control protein expression has several benefits including the ability to create stable cell lines that express potentially cytotoxic proteins. Therefore when used in tandem, these two methods constitute a new and improved approach for dissecting the cellular role and transcriptional targets of many transcription factors. Here we illustrate this integrated approach by using a conditional dominant-negative Elk-1 protein to identify candidate Elk-1-regulated target genes.

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