High mobility group I/Y protein functions as a specific cofactor for Oct-2A: mapping of interaction domains

Abdulkadir, Sarki A.; Casolaro, Vincenzo; Tai, Albert; Thanos, Dimitris; Ono, Santa Jeremy

doi:10.1002/jlb.64.5.681

Cited by 20 publications

(19 citation statements)

References 58 publications

(94 reference statements)

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“…Finally, we demonstrate that the paired-like homeodomain protein Crx, which binds to the BAT-1 site, physically interacts with HMG I(Y) and specifically with their DNA-binding domains. This interaction is reminiscent of interactions between HMG I(Y) proteins and the octamer family of POU-homeodomain proteins, which others and we have previously shown to facilitate the octamer factor binding and activity (Abdulkadir et al, , 1998Leger et al, 1995). In conclusion, this report provides the first evidence for an important role for HMG I(Y) proteins in gene activation in terminally differentiated cells and identifies an HMG-dependent gene in photoreceptor cells.…”

Section: Abstract: Hmg I(y); Crx; Rhodopsin; Retinoblastoma; Retina;mentioning

confidence: 63%

The Architectural Transcription Factor High Mobility Group I(Y) Participates in Photoreceptor-Specific Gene Expression

et al. 2000

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Section: Abstract: Hmg I(y); Crx; Rhodopsin; Retinoblastoma; Retina;mentioning

confidence: 63%

The Architectural Transcription Factor High Mobility Group I(Y) Participates in Photoreceptor-Specific Gene Expression

et al. 2000

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“…HMG I(Y) is a nonhistone, chromatin-associated nuclear protein that binds to the minor groove of AT-rich stretches of DNA (reviewed in references 6, 17, and 18). It can alter the binding of various transcription factors through its effects on DNA structure as well as through direct proteinprotein interactions (1). HMG I(Y) binds to the A3/4 region of the insulin promoter (data not shown).…”

Section: Methodsmentioning

confidence: 98%

“…HMG I proteins can bind to transcription factors as well as DNA, as exemplified by the interaction between HMG I(Y) and the Pou domain of the POU homeodomain protein Oct-2A (1). In an in vitro interaction assay, both wild-type PDX-1 and the homeodomain of PDX-1 associate with HMG I(Y) (Fig.…”

Section: Methodsmentioning

confidence: 99%

The Homeodomain of PDX-1 Mediates Multiple Protein-Protein Interactions in the Formation of a Transcriptional Activation Complex on the Insulin Promoter

Ohneda

Mirmira

Wang

et al. 2000

Molecular and Cellular Biology

184

168

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Like expression of other cell-type-specific genes, expression of the insulin gene depends on the actions of a unique set of nuclear activators. These activators cooperate synergistically in building a transcriptional activation complex that binds to the regulatory domains of the gene and activates the basal RNA polymerase machinery (reviewed in reference 7). The complexity and specificity of the interactions among these activators limit the cell types capable of building a functional activation complex. Dissection of these interactions provides insight into the mechanism by which insulin expression is limited to the correct cell type.In adult mammals, activation of the insulin gene is tightly restricted to the ␤ cells in the pancreatic islets of Langerhans, where it is expressed at high levels. This specificity is reflected in the restricted function of the insulin promoter, the proximal few hundred base pairs of which can replicate the specificity of the intact gene (19,50). Because of the complexity of the intact promoter (9, 13, 24), a short portion of the rat insulin I promoter between bp Ϫ247 and Ϫ197 upstream from the transcription initiation site has been used as a model of the types of synergistic interactions that combine to give the characteristic activity of the full promoter (15). This 50-bp fragment contains at least three distinct DNA-binding sites named E2, A3, and A4 (13). The E and A elements synergize: neither has significant activity on its own, but in combination E and A elements produce ␤-cell specific transcriptional activation (15,23).The E2 element functions as a recognition site for dimers of basic helix-loop-helix (bHLH) proteins, including a heterodimer of the ubiquitous bHLH protein E47/Pan1 and the neuroendocrine specific bHLH protein BETA2/NeuroD1 (35). The A elements each contain the sequence TAAT and have been shown to bind to several homeodomain proteins found in ␤-cell nuclei (12,16,22, 32,37 (16,38,40).The LIM homeodomain protein Lmx1.1 contains two LIM domains that form zinc-binding structures in the amino end of the molecule. The second of these two LIM domains (LIM2) directly binds to the bHLH domain of E47/Pan1 and mediates the synergy between Lmx1.1 and E47/Pan1. This interaction is specific, since analogous domains from other LIM proteins and bHLH proteins cannot substitute for the LIM2 domain of Lmx1.1 or the bHLH domain of E47/Pan1, respectively (20).PDX-1 plays an important role both in the development of the pancreas and in maintaining ␤-cell function. Mice with a targeted disruption of the pdx1 gene selectively lack a pancreas (2, 21, 36). Similar pancreatic agenesis has been found in a human patient with a single nucleotide deletion in the pdx1 gene (46). If the pancreas is allowed to develop with an intact pdx1 gene, and the pdx1 gene is disrupted only in mature ␤ cells, diabetes ensues due to impaired ␤-cell function (3). This

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“…HMG I proteins are essential for inducible expression of several genes including the interferon-␤, the HLA-DRA class II major histocompatibility complex, and E-selectin genes (12)(13)(14)(15). HMG I proteins could participate in gene activation by inducing conformational changes in a cis-element (16) through interaction with a transcription factor (8,12,17,18), by bridging two neighboring factors (19,20), or by displacing histone H1 from nucleosomes (21,22).…”

mentioning

confidence: 99%

Transgenic Mice Expressing a Truncated Form of the High Mobility Group I-C Protein Develop Adiposity and an Abnormally High Prevalence of Lipomas

Arlotta¹,

Tai²,

Manfioletti³

et al. 2000

Journal of Biological Chemistry

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139

109

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High mobility group I/Y protein functions as a specific cofactor for Oct-2A: mapping of interaction domains

Cited by 20 publications

References 58 publications

The Architectural Transcription Factor High Mobility Group I(Y) Participates in Photoreceptor-Specific Gene Expression

The Architectural Transcription Factor High Mobility Group I(Y) Participates in Photoreceptor-Specific Gene Expression

The Homeodomain of PDX-1 Mediates Multiple Protein-Protein Interactions in the Formation of a Transcriptional Activation Complex on the Insulin Promoter

Transgenic Mice Expressing a Truncated Form of the High Mobility Group I-C Protein Develop Adiposity and an Abnormally High Prevalence of Lipomas

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