Sp1 and AP2 transcription factors are required for the human fragile mental retardation promoter activity in SK-N-SH neuronal cells

Carrillo, Carmen; Cisneros, Bulmaro; Montañéz, Cecilia

doi:10.1016/s0304-3940(99)00798-3

Cited by 16 publications

(20 citation statements)

References 21 publications

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“…Moreover, when a CREB consensus oligonucleotide is used as a probe with our extracts, a shifted product is seen (data not shown). We found no evidence for any other factor binding including AP2 (data not shown), which has also been reported to be involved in FMR1 regulation (15). The differences between our data and those previously reported might reflect differences between the source of the material used to prepare the nuclear extracts and other experimental conditions.…”

Section: Fmr1 Gene Regulationcontrasting

confidence: 89%

“…This hyperreactivity is absent in individuals with fragile X syndrome and is therefore thought to reflect some DNA structure that is associated with transcription (5). The transcription factors Zeste (5), AP2 (15), and CREB (13) have all been suggested to be important for FMR1 regulation. However the binding sites for these factors were not conserved (shown in the open boxes Fig.…”

Section: Phylogenetic Footprinting Of the 5ј End Of Fmr1 Gene Identifmentioning

confidence: 99%

“…Sp3 Binds a FMR1 Promoter Subfragment-Factor binding to the 2 GC boxes in the human promoter has been reported in fibroblasts and lymphoid cells (5,6) and in vitro on a 71-bp promoter-containing fragment in extracts of the neuronally derived cell line SK-N-SH (15). However, GC-box-specific factors did not bind the full-length promoter in any of our extracts under a variety of reaction conditions; unlabeled GC-box oligonucleotides did not alter the EMSA profile (Fig.…”

Section: Fmr1 Gene Regulationmentioning

confidence: 99%

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Interaction of the Transcription Factors USF1, USF2, and α-Pal/Nrf-1 with the FMR1 Promoter

Kumari

Usdin

2001

Journal of Biological Chemistry

105

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Hypermethylation of the FMR1 promoter reduces its transcriptional activity, resulting in the mental retardation and macroorchidism characteristic of Fragile X syndrome. How exactly methylation causes transcriptional silencing is not known but is relevant if current attempts to reactivate the gene are to be successful. Understanding the effect of methylation requires a better understanding of the factors responsible for FMR1 gene expression. To this end we have identified five evolutionarily conserved transcription factor binding sites in this promoter and shown that four of them are important for transcriptional activity in neuronally derived cells. We have also shown that USF1, USF2, and ␣؊Pal/Nrf-1 are the major transcription factors that bind the promoter in brain and testis extracts and suggest that elevated levels of these factors account in part for elevated FMR1 expression in these organs. We also show that methylation abolishes ␣؊Pal/Nrf-1 binding to the promoter and affects binding of USF1 and USF2 to a lesser degree. Methylation may therefore inhibit FMR1 transcription not only by recruiting histone deacetylases but also by blocking transcription factor binding. This suggests that for efficient reactivation of the FMR1 promoter, significant demethylation must occur and that current approaches to gene reactivation using histone deacetylase inhibitors alone may therefore have limited effect.Fragile X syndrome is caused by the expansion of a CGG repeat in the 5Ј-untranslated region of the fragile X mental retardation (FMR1) gene (1, 2). This results in hypermethylation of the promoter and transcriptional silencing (3). The major symptoms of fragile X syndrome, mental retardation and macroorchidism, are consistent with the observation that high levels of FMR1 expression occurs in specific cells in brain and testis (4). The GC-rich human FMR1 promoter lacks a typical TATA-box and contains several potential Sp1 binding sites as well as an E-box and putative binding sites for the transcription factors ␣-Pal/Nrf-1, 1 AP2, AGP/EBP, and Zeste (5). Four regions of protein binding in the unmethylated promoter of the FMR1 gene have been described by in vivo dimethyl sulfate footprinting analysis in human fibroblasts, peripheral lymphocytes, and lymphoblastoid cell lines (5, 6). These footprints correspond to the ␣-Pal/Nrf-1 site, 2 GC-boxes, and the E-box. However, the transcription factors that interact with these sites have not yet been identified. Moreover, whereas these footprints do reflect in vivo interactions, their relevance to the regulation of FMR1 transcription in brain and testis, the two major affected organs, is unknown.Because FMR1 knockout mice demonstrate learning deficits and macroorchidism similar to those seen in fragile X patients (7), and mice show patterns of temporal and tissue-specific FMR1 expression similar to humans (8), many of the control elements important for FMR1 gene regulation are also likely to be evolutionarily conserved. To identify conserved promoter elements, we compared the ...

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Section: Fmr1 Gene Regulationcontrasting

confidence: 89%

Section: Phylogenetic Footprinting Of the 5ј End Of Fmr1 Gene Identifmentioning

confidence: 99%

Section: Fmr1 Gene Regulationmentioning

confidence: 99%

See 1 more Smart Citation

Interaction of the Transcription Factors USF1, USF2, and α-Pal/Nrf-1 with the FMR1 Promoter

Kumari

Usdin

2001

Journal of Biological Chemistry

105

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“…AP2 is highly expressed in the CNS and is critical for normal neuronal development [36]. Our results thus suggest that despite the lack of extensive sequence conservation, the FMR1 and FXR2 promoters may be more similar than they appear: they are both TATA-less promoters that are regulated by Sp1, Nrf1 and AP2 [11][12][13][14][15] and have CGG · CCG repeats in 5 -UTR.…”

Section: The Role Of Various Transcription Factors In Regulation Of Tmentioning

confidence: 84%

“…While many factors important for the regulation of the FMR1 gene have been identified [11][12][13][14][15][16], nothing is known about the regulation of the FXR2 gene. Despite the conservation in their coding sequences and the similarity in their pattern of tissue expression, the promoters of these genes are not similar at the sequence level.…”

Section: Introductionmentioning

confidence: 99%

NF-Y, AP2, Nrf1 and Sp1 regulate the fragile X-related gene 2 (FXR2)

Mahishi

Usdin

2006

Biochemical Journal

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Fragile X syndrome, the most common heritable form of mental retardation, is caused by silencing of the FMR1 (fragile X mental retardation-1 gene). The protein product of this gene, FMRP (fragile X mental retardation protein), is thought to be involved in the translational regulation of mRNAs important for learning and memory. In mammals, there are two homologues of FMRP, namely FXR1P (fragile X-related protein 1) and FXR2P. Disruption of Fxr2 in mice produces learning and memory deficits, and Fmr1 and Fxr2 double-knockout mice have exaggerated impairments in certain neurobehavioral phenotypes relative to the single gene knockouts. This has led to the suggestion that FMR1 and FXR2 functionally overlap and that increasing the expression of FXR2P may ameliorate the symptoms of an FMRP deficiency. Interestingly, the region upstream of the FXR2 translation start site acts as a bidirectional promoter in rodents, driving transcription of an alternative transcript encoding the ABP (androgen-binding protein) [aABP (alternative ABP promoter)]. To understand the regulation of the human FXR2 gene, we cloned the evolutionarily conserved region upstream of the FXR2 translation start site and showed that it also has bidirectional promoter activity in both neuronal and muscle cells as evidenced by luciferase reporter assay studies. Alignment of the human, mouse, rat, rabbit and dog promoters reveals several highly conserved transcription factorbinding sites. Gel electrophoretic mobility-shift assays, chromatin immunoprecipitation studies and co-transfection experiments with plasmids expressing these transcription factors or dominantnegative versions of these factors showed that NF-YA (nuclear transcription factor Yα), AP2 (activator protein 2), Nrf1 (nuclear respiratory factor/α-Pal) and Sp1 (specificity protein 1) all bind to the FXR2 promoter both in vitro and in vivo and positively regulate the FXR2 promoter.

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Immunocytochemical characterization of FMRP, FXR1P and FXR2P during embryonic development in the mouse

et al. 2000

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Sp1 and AP2 transcription factors are required for the human fragile mental retardation promoter activity in SK-N-SH neuronal cells

Cited by 16 publications

References 21 publications

Interaction of the Transcription Factors USF1, USF2, and α-Pal/Nrf-1 with the FMR1 Promoter

Interaction of the Transcription Factors USF1, USF2, and α-Pal/Nrf-1 with the FMR1 Promoter

NF-Y, AP2, Nrf1 and Sp1 regulate the fragile X-related gene 2 (FXR2)

Immunocytochemical characterization of FMRP, FXR1P and FXR2P during embryonic development in the mouse

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