scholarly journals Constitutively active FOXO1a and a DNA-binding domain mutant exhibit distinct co-regulatory functions to enhance progesterone receptor A activity

2007 ◽  
Vol 38 (6) ◽  
pp. 673-690 ◽  
Author(s):  
Michael D Rudd ◽  
Ignacio Gonzalez-Robayna ◽  
Inmaculada Hernandez-Gonzalez ◽  
Nancy L Weigel ◽  
William E Bingman ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Dna Binding ◽  
Hormone Receptors ◽  
Binding Domain ◽  
Nuclear Hormone Receptors ◽  
Dna Binding Domain ◽  
Transactivation Domain ◽  
Response Element ◽  
Regulatory Functions ◽  
Constitutively Active

FOXO (Forkhead box O1 transcription factors) factors interact with and modify the activity of other transcription factors, including nuclear hormone receptors. However, not all of the structural domains within the FOXO proteins that mediate these functional interactions have been clearly defined. To address this issue, we used a constitutively active (nuclear) mutant of FOXO1a (designated FOXOA3) and within FOXOA3 made additional mutations to alter the putative nuclear hormone interacting domain (NID), minimal activation domain (MAD), DNA-binding domain (DBD), and the N terminus. We document that FOXOA3 enhanced the hormone-dependent transcriptional activity of liganded progesterone receptors A (PGRA) on a glucocorticoid response element-responsive promoter, PGRA on the insulin-like growth factor-binding protein 1 promoter, and estrogen receptor α on an estrogen response element-responsive promoter. The effects of FOXOA3 on PGRA were dependent, in part, on an intact NID, the MAD, and N-terminal domain. In striking contrast, a FOXOA3 DNA-binding mutant (FOXOA3-mDBD) modulated PGRA, PGRB, and ESR1 activities by distinctly different mechanisms, markedly elevating ligand-independent activity of these nuclear hormone receptors even in the double mutant lacking the MAD. Furthermore, both FOXOA3 and FOXOA3-mDBD enhanced the activity of a transcriptionally defective PGRA lacking its AF1 transactivation domain, indicating that this region of the receptor is not essential in this context. Since FOXOA3, FOXOA3-mDBD, and FOXOA3-mNID all bound PGRA in a GST pull-down assay, it appears that the LXXLL (leucine–X–X–leucine–leucine) motif within the NID is not critical for FOXOA3 interactions with PGRA, but may modify the recruitment of other co-regulatory molecules. Collectively, the results show that FOXOA3 exerts co-regulatory functions independent of DNA binding and that the DNA-binding defective form of FOXO1a is transcriptionally active as a co-regulator of these nuclear hormone receptors.

scholarly journals Transactivation Functions of the N-Terminal Domains of Nuclear Hormone Receptors: Protein Folding and Coactivator Interactions

2003 ◽  
Vol 17 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Raj Kumar ◽  
E. Brad Thompson
Keyword(s):  
Dna Binding ◽  
Protein Interactions ◽  
Hormone Receptors ◽  
Nuclear Hormone Receptor ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Protein Protein Interactions ◽  
Carboxy Terminal ◽  
And Function ◽  
Terminal Domains

Abstract The N-terminal domains (NTDs) of many members of the nuclear hormone receptor (NHR) family contain potent transcription-activating functions (AFs). Knowledge of the mechanisms of action of the NTD AFs has lagged, compared with that concerning other important domains of the NHRs. In part, this is because the NTD AFs appear to be unfolded when expressed as recombinant proteins. Recent studies have begun to shed light on the structure and function of the NTD AFs. Recombinant NTD AFs can be made to fold by application of certain osmolytes or when expressed in conjunction with a DNA-binding domain by binding that DNA-binding domain to a DNA response element. The sequence of the DNA binding site may affect the functional state of the AFs domain. If properly folded, NTD AFs can bind certain cofactors and primary transcription factors. Through these, and/or by direct interactions, the NTD AFs may interact with the AF2 domain in the ligand binding, carboxy-terminal portion of the NHRs. We propose models for the folding of the NTD AFs and their protein-protein interactions.

Deciphering the enigma of missing DNA binding domain of LacI family transcription factors

2021 ◽  
Vol 713 ◽  
pp. 109060
Author(s):  
Neetu Neetu ◽  
Madhusudhanarao Katiki ◽  
Jai Krishna Mahto ◽  
Monica Sharma ◽  
Anoop Narayanan ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Dna Binding ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Laci Family

Molecular genetics of chromosome translocations involving EWS and related family members

1999 ◽  
Vol 1 (3) ◽  
pp. 127-138 ◽  
Author(s):  
JUNGHO KIM ◽  
JERRY PELLETIER
Keyword(s):  
Transcription Factors ◽  
Dna Binding ◽  
Molecular Genetics ◽  
Family Members ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Chromosome Translocations ◽  
Amino Terminal ◽  
Terminal Domain ◽  
Related Family

Kim, Jungho, and Jerry Pelletier. Molecular genetics of chromosome translocations involving EWS and related family members. Physiol. Genomics 1: 127–138, 1999.—Many types of sarcomas are characterized by specific chromosomal translocations that appear to result in the production of novel, tumor-specific chimeric transcription factors. Many of these show striking similarities: the emerging picture is that the amino-terminal domain of the fusion product is donated by the Ewing's sarcoma gene ( EWS) or a related member from the same gene family, whereas the carboxy-terminal domain often consists of a DNA-binding domain derived from one of a number of transcription factors. Given the observation that the different translocation partners of the EWS protooncogene are associated with distinct types of sarcomas, the functional consequence of fusing EWS (or a related family member) to a different DNA-binding domain can only be understood in the context of functional studies that define the specificity of action of the different fusion products. An understanding of the molecular structure and function of these translocations provides new methods for diagnosis and novel targets for therapeutics.

scholarly journals Regulation of Cell Cycle Transcription Factor Swi4 through Auto-Inhibition of DNA Binding

1999 ◽  
Vol 19 (10) ◽  
pp. 6729-6741 ◽  
Author(s):  
Kristin Baetz ◽  
Brenda Andrews
Keyword(s):  
Cell Cycle ◽  
Transcription Factors ◽  
Dna Binding ◽  
Binding Domain ◽  
Terminal Region ◽  
Full Length ◽  
Intramolecular Interactions ◽  
Dna Binding Domain ◽  
C Terminus ◽  
Binding Factor

ABSTRACTInSaccharomyces cerevisiae, two transcription factors, SBF (SCB binding factor) and MBF (MCB binding factor), promote the induction of gene expression at the G1/S-phase transition of the mitotic cell cycle. Swi4 and Mbp1 are the DNA binding components of SBF and MBF, respectively. The Swi6 protein is a common subunit of both transcription factors and is presumed to play a regulatory role. SBF binding to its target sequences, the SCBs, is a highly regulated event and requires the association of Swi4 with Swi6 through their C-terminal domains. Swi4 binding to SCBs is restricted to the late M and G1phases, when Swi6 is localized to the nucleus. We show that in contrast to Swi6, Swi4 remains nuclear throughout the cell cycle. This finding suggests that the DNA binding domain of Swi4 is inaccessible in the full-length protein when not complexed with Swi6. To explore this hypothesis, we expressed Swi4 and Swi6 in insect cells by using the baculovirus system. We determined that partially purified Swi4 cannot bind SCBs in the absence of Swi6. However, Swi4 derivatives carrying point mutations or alterations in the extreme C terminus were able to bind DNA or activate transcription in the absence of Swi6, and the C terminus of Swi4 inhibited Swi4 derivatives from binding DNA intrans. Full-length Swi4 was determined to be monomeric in solution, suggesting an intramolecular mechanism for auto-inhibition of binding to DNA by Swi4. We detected a direct in vitro interaction between a C-terminal fragment of Swi4 and the N-terminal 197 amino acids of Swi4, which contain the DNA binding domain. Together, our data suggest that intramolecular interactions involving the C-terminal region of Swi4 physically prevent the DNA binding domain from binding SCBs. The interaction of the carboxy-terminal region of Swi4 with Swi6 alleviates this inhibition, allowing Swi4 to bind DNA.

scholarly journals A New Coactivator Function for Zac1's C2H2 Zinc Finger DNA-Binding Domain in Selectively Controlling PCAF Activity

2008 ◽  
Vol 28 (19) ◽  
pp. 6078-6093 ◽  
Author(s):  
Anke Hoffmann ◽  
Dietmar Spengler
Keyword(s):  
Transcription Factors ◽  
Dna Binding ◽  
Zinc Finger ◽  
Transcriptional Control ◽  
Zinc Finger Protein ◽  
Embryonic Stem ◽  
Binding Domain ◽  
Dna Binding Domain ◽  
Histone H4 ◽  
Histone H4 Acetylation

ABSTRACT The generally accepted paradigm of transcription by regulated recruitment defines sequence-specific transcription factors and coactivators as separate categories that are distinguished by their abilities to bind DNA autonomously. The C2H2 zinc finger protein Zac1, with an established role in canonical DNA binding, also acts as a coactivator. Commensurate with this function, p73, which is related to p53, is here shown to recruit Zac1, together with the coactivators p300 and PCAF, to the p21Cip1 promoter during the differentiation of embryonic stem cells into neurons. In the absence of autonomous DNA binding, Zac1's zinc fingers stabilize the association of PCAF with p300, suggesting its scaffolding function. Furthermore, Zac1 regulates the affinities of PCAF substrates as well as the catalytic activities of PCAF to induce a selective switch in favor of histone H4 acetylation and thereby the efficient transcription of p21Cip1. These results are consistent with an authentic coactivator function of Zac1's C2H2 zinc finger DNA-binding domain and suggest coactivation by sequence-specific transcription factors as a new facet of transcriptional control.

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