A universal target sequence is bound in vitro by diverse homeodomains

Kalionis, Bill; O’Farrell, Patrick H.

doi:10.1016/0925-4773(93)90023-q

Cited by 66 publications

(54 citation statements)

References 66 publications

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“…After the identification of the genes encoding several adhesion molecules, such as cytotactin (30), N-CAM (31,32), and L-CAM (25), as target genes for homeoproteins (33), our results indicate that bFGF is the first growth factor involved in the complex network underlying HOX gene effects on cell proliferation and differentiation.…”

Section: Discussionmentioning

confidence: 99%

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HOXB7 Constitutively Activates Basic Fibroblast Growth Factor in Melanomas

Caré

Silvani

Meccia

et al. 1996

Molecular and Cellular Biology

192

174

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Homeobox (HOX) genes control axial specification during mammalian development and also regulate skin morphogenesis. Although selected HOX genes are variably expressed in leukemias and kidney and colon cancer cell lines, their relationship with the neoplastic phenotype remains unclear. In both normal development and neoplastic transformation, HOX target genes are largely unknown. We investigated the expression and function of HOXB cluster genes in human melanoma. The HOXB7 gene was constitutively expressed in all 25 melanoma cell lines and analyzed under both normal and serum-starved conditions, as well as in in vivo primary and metastatic melanoma cells; conversely, HOXB7 was expressed in proliferating but not quiescent normal melanocytes. Treatment of melanoma cell lines with antisense oligomers targeting HOXB7 mRNA markedly inhibited cell proliferation and specifically abolished expression of basic fibroblast growth factor (bFGF) mRNA. Band shift and cotransfection experiments showed that HOXB7 directly transactivates the bFGF gene through one out of five putative homeodomain binding sites present in its promoter. These novel findings indicate a key role for constitutive HOXB7 expression in melanoma cell proliferation via bFGF. The results also raise the possibility that growth factor genes are critical HOX target genes in other developmental and/or neoplastic cell systems.

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Section: Discussionmentioning

confidence: 99%

“…5 indicated a direct and selective interaction of the HOXB7 protein with the sequence encompassing nucleotides ϩ130 to ϩ159 of the bFGF promoter. Although the ATTA box is shared among several homeoproteins (33), unique flanking sequences may account for their high-affinity binding.…”

Section: Resultsmentioning

confidence: 99%

HOXB7 Constitutively Activates Basic Fibroblast Growth Factor in Melanomas

Caré

Silvani

Meccia

et al. 1996

Molecular and Cellular Biology

192

174

View full text Add to dashboard Cite

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“…The initial dri cDNA clone (bk60) was isolated as described previously (16). Subsequent overlapping clones were isolated by screening a gt11 Drosophila 3-to 18-h embryo cDNA library (Clontech) with regions of bk60 as the probes.…”

Section: Methodsmentioning

confidence: 99%

“…The similarity of the in vitro DNA-binding characteristics of homeodomain proteins was particularly evident in a screen that identified a large number of homeodomain proteins by their ability to bind an oligonucleotide containing a consensus EN binding site (16). One of the genes identified in that screen, originally termed bk60 but here renamed dead ringer (dri), is the subject of this report.…”

mentioning

confidence: 99%

Characterization of the dead ringer Gene Identifies a Novel, Highly Conserved Family of Sequence-Specific DNA-Binding Proteins

Gregory

Kortschak

Kalionis

et al. 1996

Molecular and Cellular Biology

147

149

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We report the identification of a new family of DNA-binding proteins from our characterization of the dead ringer (dri) gene of Drosophila melanogaster. We show that dri encodes a nuclear protein that contains a sequence-specific DNA-binding domain that bears no similarity to known DNA-binding domains. A number of proteins were found to contain sequences homologous to this domain. Other proteins containing the conserved motif include yeast SWI1, two human retinoblastoma binding proteins, and other mammalian regulatory proteins. A mouse B-cell-specific regulator exhibits 75% identity with DRI over the 137-amino-acid DNA-binding domains of these proteins, indicating a high degree of conservation of this domain. Gel retardation and optimal binding site screens revealed that the in vitro sequence specificity of DRI is strikingly similar to that of many homeodomain proteins, although the sequence and predicted secondary structure do not resemble a homeodomain. The early general expression of dri and the similarity of DRI and homeodomain in vitro DNA-binding specificity compound the problem of understanding the in vivo specificity of action of these proteins. Maternally derived dri product is found throughout the embryo until germ band extension, when dri is expressed in a developmentally regulated set of tissues, including salivary gland ducts, parts of the gut, and a subset of neural cells. The discovery of this new, conserved DNA-binding domain offers an explanation for the regulatory activity of several important members of this class and predicts significant regulatory roles for the others.The large number of developmentally significant transcription factors found in a wide variety of metazoans can be grouped into a surprisingly small number of gene families, each encoding proteins with a related DNA-binding or dimerization motif (8,14). Protein motifs such as the homeodomain, zinc finger, bZIP, POU, Ets, and Forkhead/HNF-3 domains have been widely conserved during evolution and are used in a variety of regulatory roles.Within the homeodomain group of regulators (see reference 12 for a review), DNA-binding domains encoded by functionally different genes exhibit striking similarities in DNA-binding specificity. For example, the Ultrabithorax and engrailed genes encode homeodomain proteins (UBX and EN, respectively) that bind in a sequence-specific fashion to the same DNA sequences in vitro (1, 7). One of the ways in which the specificity of homeodomain protein action can be conferred in vivo, despite this similarity in binding properties, is by association with other factors. For example, the affinity of UBX for particular binding sites is modified by cooperative interactions with the EXD homeodomain protein (4, 32). From these recent reports and from the genetic analysis of the in vivo role of the homeodomain (11, 18), it is clear that our understanding of gene regulation during development is far from complete, even at the level of identification of the factors involved.The similarity of the in vitro DNA-binding...

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“…Experiments indicated that Sox and POU proteins work together to activate, while homeodomain proteins repress and limit expression of CNS genes. Interestingly, several motifs identified here as important for regulation in midline glia of Drosophila resemble binding sites for Sox (G1: CACAAT; Wegner 1999), POU (G4: ATGCAAAT, G6: ATGCAACA, and G8: ATGCGTGG; Pankratova and Polanovsky 1998), and homeodomain proteins (G5: ATTTTATC; Kalionis and O'Farrell 1993).…”

Section: Discussionmentioning

confidence: 99%

Identification of Motifs That Are Conserved in 12 Drosophila Species and Regulate Midline Glia vs. Neuron Expression

2008

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Functional complexity of the central nervous system (CNS) is reflected by the large number and diversity of genes expressed in its many different cell types. Understanding the control of gene expression within cells of the CNS will help reveal how various neurons and glia develop and function. Midline cells of Drosophila differentiate into glial cells and several types of neurons and also serve as a signaling center for surrounding tissues. Here, we examine regulation of the midline gene, wrapper, required for both neuron-glia interactions and viability of midline glia. We identify a region upstream of wrapper required for midline expression that is highly conserved (87%) between 12 Drosophila species. Site-directed mutagenesis identifies four motifs necessary for midline glial expression: (1) a Single-minded/Tango binding site, (2) a motif resembling a pointed binding site, (3) a motif resembling a Sox binding site, and (4) a novel motif. An additional highly conserved 27 bp are required to restrict expression to midline glia and exclude it from midline neurons. These results suggest short, highly conserved genomic sequences flanking Drosophila midline genes are indicative of functional regulatory regions and that small changes within these sequences can alter the expression pattern of a gene.

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A universal target sequence is bound in vitro by diverse homeodomains

Cited by 66 publications

References 66 publications

HOXB7 Constitutively Activates Basic Fibroblast Growth Factor in Melanomas

HOXB7 Constitutively Activates Basic Fibroblast Growth Factor in Melanomas

Characterization of the dead ringer Gene Identifies a Novel, Highly Conserved Family of Sequence-Specific DNA-Binding Proteins

Identification of Motifs That Are Conserved in 12 Drosophila Species and Regulate Midline Glia vs. Neuron Expression

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