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M H Werner

Publications and source records attributed to M H Werner.

At least 19 recordsLinked to original sources
PubMed2002

[Conclusions from the Viagra case? Definition of disease in social legislation as exemplified by erectile dysfunction].

The article describes the controversy about the question whether statutory social health insurances are obliged to reimburse the costs for the treatment of erectile dysfunction. Next to the question whether the 'Bundesausschuss der Arzte und Krankenkassen' was entitled to decide it was highly controversial whether erectile dysfunction is a disease according to the laws of social insurance. This enforces more general considerations regarding the possibility to define disease and the relevancy of a concept of disease for the justification and limitation of socially financed services in medicine.

Erectile Dysfunction↗
PubMed2001

Flipping a genetic switch by subunit exchange.

The bacteriophage T4 AsiA protein is a multifunctional protein that simultaneously acts as both a repressor and activator of gene expression during the phage life cycle. These dual roles with opposing transcriptional consequences are achieved by modification of the host RNA polymerase in which AsiA binds to conserved region 4 (SR4) of sigma(70), altering the pathway of promoter selection by the holoenzyme. The mechanism by which AsiA flips this genetic switch has now been revealed, in part, from the three-dimensional structure of AsiA and the elucidation of its interaction with SR4. The structure of AsiA is that of a novel homodimer in which each monomer is constructed as a seven-helix bundle arranged in four overlapping helix-loop-helix elements. Identification of the protein interfaces for both the AsiA homodimer and the AsiA-sigma(70) complex reveals that these interfaces are coincident. Thus, the AsiA interaction with sigma(70) necessitates that the AsiA homodimer dissociate to form an AsiA-SR4 heterodimer, exchanging one protein subunit for another to alter promoter choice by RNA polymerase.

Bacteriophage T4↗
PubMed2001

Functional mutagenesis of AML1/RUNX1 and PEBP2 beta/CBF beta define distinct, non-overlapping sites for DNA recognition and heterodimerization by the Runt domain.

The Runt domain family of transcription factors play key roles in transcriptional regulation of definitive hematopoiesis and osteogenesis. This transcription factor family is characterized by a DNA-binding alpha-subunit harboring the Runt domain and a secondary subunit, beta, which binds to the Runt domain and enhances its interaction with DNA. Missense mutations in the Runt domain from either the blood or bone-related gene product are associated with the onset of acute human leukemia as well as a disease of skeletal patterning known as cleidocranial dysplasia. NMR "footprinting" analysis of Runt domain/beta/DNA ternary complexes in solution previously identified the likely residues that form the heterodimerization and DNA-binding surfaces of the Runt domain. Functional mutagenesis at 37 positions in the Runt domain or beta confirms the original identification of these interaction surfaces and reveals that the heterodimerization and DNA-binding surfaces of the Runt domain occur at distinct, non-overlapping sites within the domain. The analysis of an additional 21 disease-related missense mutations identified from patients with either blood or bone disease demonstrates that the primary defect in these patients is a failure in DNA-recognition by the Runt domain. The molecular basis for the DNA-binding defect is analyzed in the context of the three-dimensional structure of the Runt domain in binary and ternary protein/DNA complexes.

Amino Acid Substitution↗
PubMed2001

Uniform 13C/15N-labeling of DNA by tandem repeat amplification.

An optimized procedure has been described for the large-scale production of stable isotopeenriched duplex oligonucleotides of designed sequence. Large-scale production of labeled nucleotide triphosphates can be produced in this procedure simultaneously with labeled proteins, thereby providing synthetic dNMP precursors at no additional cost. The procedure is robust, with a minimum product:template yield of 800:1 overall, and produces > 99% single-length product. Tandem repeat PCR amplification is a general approach to large scale synthesis of duplex oligonucleotides and may have applications to both NMR and X-ray methods, particularly for product lengths in excess of 25 base pairs where failed sequences from solid-phase synthesis can be difficult to remove chromatographically. A drawback of the present approach is that the product is a duplex of two equal-length strands, making single-stranded products more difficult to prepare. For this reason, it could be preferable to produce single-stranded products by the [figure: see text] method of Zimmer and Crothers. Although a single base type can be selectively enriched in this approach, chemical synthesis will provide greater flexibility for labeled DNAs requiring site-specific labels at only one or a small number of nucleotide positions in the sequence. Therefore, maximum flexibility in labeling patterns can be realized by judicious choice of labeling method appropriate to the type of DNA product and extent of isotopic enrichment desired.

Base Sequence↗
PubMed1999

Immunoglobulin motif DNA recognition and heterodimerization of the PEBP2/CBF Runt domain.

The polyomavirus enhancer binding protein 2 (PEBP2) or core binding factor (CBF) is a heterodimeric enhancer binding protein that is associated with genetic regulation of hematopoiesis and osteogenesis. Aberrant forms of PEBP2/CBF are implicated in the cause of the acute human leukemias and in a disorder of bone development known as cleidocranial dysplasia. The common denominator in the natural and mutant forms of this protein is a highly conserved domain of PEBP2/CBF alpha, termed the Runt domain (RD), which is responsible for both DNA binding and heterodimerization with the beta subunit of PEBP2/CBF. The three-dimensional structure of the RD bound to DNA has been determined to be an S-type immunoglobulin fold, establishing a structural relationship between the RD and the core DNA binding domains of NF-kappaB, NFAT1, p53 and the STAT proteins. NMR spectroscopy of a 43.6 kD RD-beta-DNA ternary complex identified the surface of the RD in contact with the beta subunit, suggesting a mechanism for the enhancement of RD DNA binding by beta. Analysis of leukemogenic mutants within the RD provides molecular insights into the role of this factor in leukemogenesis and cleidocranial dysplasia.

Cleidocranial Dysplasia↗
PubMed1999

Molecular insights into PEBP2/CBF beta-SMMHC associated acute leukemia revealed from the structure of PEBP2/CBF beta.

PEBP2/CBF is a heterodimeric transcription factor essential for genetic regulation of hematopoiesis and osteogenesis. DNA binding by PEBP2/CBF alpha is accomplished by a highly conserved DNA binding domain, the Runt domain (RD), whose structure adopts an S-type immunoglobulin fold when bound to DNA. The supplementary subunit beta enhances DNA binding by the RD in vitro, but its role in the control of gene expression has remained largely unknown in vivo. Chromosome 16 inversion creates a chimeric gene product fusing PEBP2/CBF beta to a portion of the smooth muscle myosin heavy chain (PEBP2/CBF beta-SMMHC) that is causally associated with the onset of acute myeloid leukemia in humans. The three-dimensional structure of PEBP2/CBF beta has been determined in solution and is shown to adopt a fold related to the beta-barrel oligomer binding motif. Direct analysis of a 43.6 kD ternary RD-beta-DNA complex identifies the likely surface of beta in contact with the RD. The structure of PEBP2/CBF beta enables a molecular understanding of the capacity of PEBP2/CBF beta-SMMHC to sequester PEBP2/CBF alpha in the cytoplasm and therefore provides a molecular basis for understanding leukemogenic transformation.

Binding Sites↗
PubMed1998

Structural homology between the Rap30 DNA-binding domain and linker histone H5: implications for preinitiation complex assembly.

The three-dimensional structure of the human Rap30 DNA-binding domain has been solved by multinuclear NMR spectroscopy. The structure of the globular domain is strikingly similar to that of linker histone H5 and its fold places Rap30 into the "winged" helix-turn-helix family of eukaryotic transcription factors. Although the domain interacts weakly with DNA, the binding surface was identified and shown to be consistent with the structure of the HNF-3/fork head-DNA complex. The architecture of the Rap30 DNA-binding domain has important implications for the function of Rap30 in the assembly of the preinitiation complex. In analogy to the function of linker histones in chromatin formation, the fold of the Rap30 DNA-binding domain suggests that its role in transcription initiation may be that of a condensation factor for preinitiation complex assembly. Functional similarity to linker histones may explain the dependence of Rap30 binding on the bent DNA environment induced by the TATA box-binding protein. Cryptic sequence identity and functional homology between the Rap30 DNA-binding domain and region 4 of Escherichia coli sigma70 may indicate that the sigma factors also possess a linker histone-like activity in the formation of a prokaryotic closed complex.

Base Sequence↗
PubMed1997

Correction of the NMR structure of the ETS1/DNA complex.

The ETS family of transcription factors consists of a group of proteins that share a highly conserved 85 amino acid DNA-binding domain (DBD). This family recognizes a consensus sequence rich in purine bases with a central GGAA motif. A comparison of the published three-dimensional structures of the DBD/DNA complexes of ETS1 by NMR [Werner et al. (1995) Cell, 83, 761-771] and the related Pu.1 by X-ray crystallography [Kodandapani et al. (1996) Nature, 380, 456-460] reveals an apparent discrepancy in which the protein domains bind with opposite polarity to their target sequences. This surprising and highly unlikely result prompted us to reexamine our NMR structure. Additional NMR experiments now reveal an error in the original interpretation of the spectra defining the orientation of the ETS1-DBD on DNA. It was originally reported that the ETS1-DBD bound to DNA with a bipartite motif involving major groove recognition via a helix-turn-helix element and minor groove recognition via protein side-chain intercalation. The presence of intercalation was deduced on the basis of numerous NOEs between several amino acids in the protein and a resonance at 12.33 ppm originally assigned to a DNA imino proton. New NMR experiments now conclusively demonstrate that this resonance, which is located within the DNA imino proton region of the spectrum, arises from the hydroxyl proton of Tyr86. Realization of this error necessitated reanalysis of the intermolecular NOEs. This revealed that the orientation of the ETS1-DBD in the complex is opposite to that originally reported and that a tryptophan residue does not intercalate into the DNA. The calculation of a new ensemble of structures based on the corrected data indicates that the structure of the ETS1-DBD/DNA complex is indeed similar to the X-ray structure of the Pu.1-DBD/DNA complex.

Amino Acid Sequence↗
PubMed1996

Stopping death cold.

The three-dimensional structure of Bcl-xL, an inhibitor of apoptosis, suggests how different combinations of proteins in the same family might be utilized to control apoptosis.

Amino Acid Sequence↗
PubMed1996

Intercalation, DNA kinking, and the control of transcription.

Biological processes involved in the control and regulation of transcription are dependent on protein-induced distortions in DNA structure that enhance the recruitment of proteins to their specific DNA targets. This function is often accomplished by accessory factors that bind sequence specifically and locally bend or kink the DNA. The recent determination of the three-dimensional structures of several protein-DNA complexes, involving proteins that perform such architectural tasks, brings to light a common theme of side chain intercalation as a mechanism capable of driving the deformation of the DNA helix. The protein scaffolds orienting the intercalating side chain (or side chains) are structurally diverse, presently comprising four distinct topologies that can accomplish the same task. The intercalating side chain (or side chains), however, is exclusively hydrophobic. Intercalation can either kink or bend the DNA, unstacking one or more adjacent base pairs and locally unwinding the DNA over as much as a full turn of helix. Despite these distortions, the return to B-DNA helical parameters generally occurs within the adjacent half-turns of DNA.

Base Composition↗
PubMed1996

Molecular determinants of mammmalian sex.

Mammalian male sex determination is controlled by a complex hierarchy of gene regulatory proteins and hormones, which promote male gonadal development and regression of the female primordia. At the core of this pathway lies the SRY protein, the master developmental switch for testicular differentiation and hence, the male sex. The three-dimensional structure of the SRY-DNA complex suggests a model of developmental gene regulation in which proteins that alter DNA structure and promote the assembly of higher-order nucleoprotein complexes play an essential role in the timing of cell specialization events.

Animals↗
PubMed1995

The solution structure of the human ETS1-DNA complex reveals a novel mode of binding and true side chain intercalation.

The solution structure of a 24.4 kDa specific complex of the DNA-binding domain (DBD) of the human ETS1 (hETS1) oncoprotein with a 17-mer DNA has been solved by NMR. The interaction of the hETS1 DBD with DNA reveals a surprising twist on the general features of helix-turn-helix (HTH)-DNA interactions. Major groove recognition involves the C-terminal two thirds of the HTH recognition helix, while minor groove recognition occurs via true intercalation of the side chain of Trp-28, which extends from the minor to the major groove. This results in a sharp kink of approximately 60 degrees and a widening of the minor groove over one-half turn of the DNA. The orientation of the HTH element of the hETS1 DBD with respect to the major groove is significantly rotated relative to other HTH proteins. These observations establish the ETS family of DNA-binding proteins as a distinct family of HTH proteins.

Amino Acid Sequence↗
PubMed1995

The increasing incidence of malignant gliomas and primary central nervous system lymphoma in the elderly.

BACKGROUND: Studies indicate that the incidence of primary malignant brain tumors in the elderly is increasing, but this may reflect increased case ascertainment due to the introduction of computed tomography (CT) scanning. In addition, tumor histology was not available in these studies. This study was conducted to determine whether the incidence of primary malignant brain tumors in the elderly in Florida is increasing and to verify the histology of these increases. METHODS: Using the number of primary malignant brain tumors reported to the Florida Cancer Data System (FCDS) when CT scanning was available, incidence rates per 100,000 people were calculated. Incidence density ratios (IDRs) were calculated for 1986-1989 relative to 1981-1984. RESULTS: Tumor incidence at ages 20-64 years increased from 5.7 in 1981-1984 to 5.9 in 1986-1989, with an IDR of 1.05 (not significant). The incidence in those aged 65 years or older rose from 14.8 to 18.3, with an IDR of 1.23 (P < 0.001). The increase was 15% in those aged 65-69, 16% in those 70-74 years, 30% in those 75-79 years, 36% in those 80-84 years, and 254% in those 85 years or older. Indicence density ratios in those aged 65 years or older were 0.92 (not significant) for astrocytoma, 2.7 (p < 0.001) for anaplastic astrocytoma, 1.32 (p < 0.001) for glioblastoma and 3.56 (p < 0.001) for lymphoma. In those aged 65+ the incidence of all cancers rose 7.6% (not significant), and the incidence of pancreatic cancer (another neoplasm that requires CT scanning for diagnosis) rose 0.34% (not significant). CONCLUSIONS: The incidence of primary brain tumors in elderly Floridians has increased. This increase is independent of increased case ascertainment associated with the introduction of CT scanning and independent of a general increase of all cancers. The rise in brain tumor incidence is observed in anaplastic astrocytoma, glioblastoma, and lymphoma but not astrocytoma. This study confirms the increase is histologically specific and not due to increased case ascertainment. Further investigation into the etiology of this increase is warranted.

Adolescent↗
PubMed1995

NMR spectroscopic analysis of the DNA conformation induced by the human testis determining factor SRY.

The conformation of an eight base pair DNA oligonucleotide duplex bound to the human testis determining factor SRY and the orientation of the protein domain within the complex have been analyzed by a variety of NMR methods which permit the selective observation of protons attached to 12C nuclei in the presence of uniformly enriched 13C/15N protein. Qualitative analysis of nuclear and rotating frame Overhauser enhancement spectra at multiple mixing times indicates that the conformation of the SRY-bound DNA is distinct from that of A- and B-DNA, in agreement with the recent three-dimensional structure determination of the complex [Werner, M. W., Huth, J. R., Gronenborn, A. M., & Clore, G. M. (1995) Cell 81, 705-714]. Selective observation of intermolecular NOEs between protein and DNA indicates that partial intercalation of a protein side chain occurs between two adenine bases in the DNA octamer. The analysis of structural features by NMR for this unusual DNA conformer and the orientation of the protein domain on the DNA is discussed. The structural features of the DNA complexed to SRY are remarkably similar, but not identical, to those of DNA complexed to the TATA-binding protein (TBP).

Amino Acid Sequence↗
PubMed1995

Molecular basis of human 46X,Y sex reversal revealed from the three-dimensional solution structure of the human SRY-DNA complex.

The solution structure of the specific complex between the high mobility group (HMG) domain of SRY (hSRY-HMG), the protein encoded by the human testis-determining gene, and its DNA target site in the promoter of the müllerian inhibitory substance gene has been determined by multidimensional NMR spectroscopy. hSRY-HMG has a twisted L shape that presents a concave surface (made up of three helices and the N- and C-terminal strands) to the DNA for sequence-specific recognition. Binding of hSRY-HMG to its specific target site occurs exclusively in the minor groove and induces a large conformational change in the DNA. The DNA in the complex has an overall 70 degrees-80 degrees bend and is helically unwound relative to classical A- and B-DNA. The structure of the complex reveals the origin of sequence-specific binding within the HMG-1/HMG-2 family and provides a framework for understanding the effects of point mutations that cause 46X,Y sex reversal at the atomic level.

Anti-Mullerian Hormone↗