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R Mantovani

Publications and source records attributed to R Mantovani.

At least 19 recordsLinked to original sources
PubMed1992

Intron-exon organization of the NF-Y genes. Tissue-specific splicing modifies an activation domain.

NF-Y is a highly conserved transcription factor which recognizes CCAAT motifs in a variety of genes. We report here the genomic organization of the genes encoding both subunits, which gives interesting clues about the functional organization of the proteins. We also report the existence of isoforms of NF-YA which result from differential splicing. These alternative splicing events map within a glutamine-rich activation domain and show a marked cell- and tissue-specific bias.

Amino Acid Sequence↗
PubMed1992

Evolutionary variation of the CCAAT-binding transcription factor NF-Y.

NF-Y is a CCAAT-specific transcription factor thought to be involved in the regulation of a variety of eukaryotic genes. It shows a striking sequence similarity with the yeast factor HAP2/3. In an attempt to trace back its evolutionary history, we succeeded in isolating NF-Y cDNA clones from a plant and from several species of vertebrates. The patterns of sequence conservation delineate potential functional domains: A central, highly conserved, domain likely responsible for DNA-binding and subunit interaction; more evolutionarily flexible flanking regions, in which variability is clustered, individualizing conserved glutamine or acidic amino-acids putatively involved in protein-protein contacts.

Amino Acid Sequence↗
PubMed1992

Monoclonal antibodies to NF-Y define its function in MHC class II and albumin gene transcription.

NF-Y is a sequence-specific DNA-binding protein which, as a heterodimer, recognizes CCAAT motifs in a variety of transcriptional promoters. We have generated a panel of monoclonal and affinity-purified polyclonal antibodies directed against various epitopes of NF-Y. These reagents are highly specific for either of the A or B subunits; we have mapped the epitopes recognized by the monoclonal antibodies to the glutamine-rich activation domain of NF-YA. The antibodies inhibit in vitro transcription from the promoters of the albumin gene and of Ea, a class II gene of the major histocompatibility complex. These data definitively demonstrate the role of NF-Y in regulating the transcription of two tissue-specific genes whose expression patterns do not overlap. Interestingly, the antibodies cannot inhibit a formed pre-initiation complex, but do block reinitiation of subsequent rounds of transcription from the same templates.

Albumins↗
PubMed1992

Incorporating knowledge to databases--a solution to complex domains.

This paper describes the design of an integrated environment to handle information on congenital heart disease patients. A three-layer model that integrates a database, a knowledge-base and a graphical user-interface is presented. The role of each layer and its connections is discussed. The advantages of using a hypertext front-end system to present and retrieve complex data are also addressed. The current status of the project and its future developments are described in the final section.

Artificial Intelligence↗
PubMed1991

The E alpha promoter: a linker-scanning analysis.

To accurately delineate the DNA sequence elements involved in the transcriptional regulation of the murine MHC class II gene E alpha, we have constructed a set of "linker-scanning" mutants of the E alpha promoter region. These were made by the gapped heteroduplex technique and result in a set of 10-bp replacement mutations, covering the -206 to -6 stretch of the promoter. The effect of these mutations on transcriptional activity was evaluated in several systems, either by transfection into cultured cells or by in vitro transcription. The data points to the now classical X and Y boxes as the most important control elements, either for constitutive expression in B lymphoma cells, or for IFN-gamma-inducible expression in macrophages. Motifs upstream of the X box also play a role, but are somewhat less critical. Overall, we find no marked difference between regulatory strategies in B lymphomas or activated macrophages.

Animals↗
PubMed1989

The deletion of the distal CCAAT box region of the A gamma-globin gene in black HPFH abolishes the binding of the erythroid specific protein NFE3 and of the CCAAT displacement protein.

Non-deletion Hereditary Persistence of Fetal Hemoglobin (HPFH) is characterized by great elevation of the synthesis, in adult age, of fetal hemoglobin (HbF), of either the A gamma or G gamma type. Strong genetic evidence indicates point mutations in the G gamma- or A gamma-globin promoter as responsible for overexpression of the mutated gene. Here we report that a 13 nucleotides deletion in the CCAAT box region of the A gamma-globin promoter, associated with greater than 100 fold overexpression of the gene, abolishes the in vitro binding of the ubiquitous factors CP1 and CDP (CCAAT displacement protein) and of the erythroid specific protein NFE3. Loss of NFE3 binding is consistent with a similar effect of the -117 G greater than A HPFH mutation, suggesting a possible role of NFE3 as a negatively acting factor. In addition, loss of CDP binding indicates that this alteration might also contribute to the HPFH phenotype in this particular case, suggesting possible heterogeneity of the mechanisms causing HPFH.

Base Sequence↗
PubMed1989

Increased erythroid-specific expression of a mutated HPFH gamma-globin promoter requires the erythroid factor NFE-1.

The -175 T greater than C mutation in the promoter of the A gamma- or G gamma-globin gene causes a 50-100 fold increase of the expression of the respective gene in adult erythroid cells (Hereditary Persistence of Fetal Hemoglobin). We show here that this mutation increases 3-9 fold the expression of a gamma-CAT reporter plasmid transfected into the erythroid cells K562, but not that of the same plasmid in non erythroid cells. The overexpression of the mutant is abolished by the mutation of the binding site for the erythroid specific factor NFE1; inactivation of the adjacent binding site for the ubiquitous factor OTF1 does not cause overexpression of the normal gamma-globin promoter. Previous results demonstrated that the -175 mutation slightly increases the in vitro binding of NFE1 and almost abolishes that of OTF1; the present functional data indicate that altered binding of NFE1, but not of OTF1, is responsible for the observed overexpression of the mutated promoter.

Adult↗
PubMed1989

DNA sequences regulating human globin gene transcription in nondeletional hereditary persistence of fetal hemoglobin.

Strong genetic evidence supports the idea that point mutations in the promoter of gamma-globin genes overexpressed in adult age [hereditary persistence of fetal hemoglobin (HPFH)] are responsible for the observed phenotype. DNA binding sites for ubiquitous and/or erythroid specific nuclear proteins correlate in location with the positions of point mutations responsible for HPFH. The analysis of the effects of one of these mutations (-175 T greater than C) on in vitro binding of nuclear proteins and on the activity of the mutated promoter in transfection assays indicates that altered binding of the erythroid-specific protein NFE-1 may be responsible for increased activity of the mutated promoter. Other HPFH mutations close to the distal CCAAT box (-117 G greater than A and 13 nucleotide deletions, -114 to -102) have complex effects on in vitro binding of nuclear proteins; their only common effect is the loss of binding of the erythroid-specific factor NFE3. If mechanisms generating the HPFH phenotype are homogeneous, NFE3 might be a negatively acting factor; alternatively, heterogeneous mechanisms might operate and HPFH might additionally be related to loss of binding to the distal CCAAT box region of either NFE1 (-117 HPFH) or of the ubiquitous CCAAT displacement protein-CDP (13 nucleotides deletion). Finally, it is also proposed that increased activity of the HPFH promoters may secondarily cause decreased expression of the delta- and beta-globin genes in cis possibly by competition between gamma- and beta-globin promoters for interaction with common regulatory elements.

Base Sequence↗
PubMed1988

The effects of HPFH mutations in the human gamma-globin promoter on binding of ubiquitous and erythroid specific nuclear factors.

Genetic evidence indicates that single point mutations in the gamma-globin promoter may be the cause of high expression of the mutated gene in the adult period (Hereditary Persistence of Fetal Hemoglobin, HPFH). Here we show that one of these mutations characterized by a T----C substitution at position -175 in a conserved octamer (ATGCAAAT) sequence, abolishes the ability of a ubiquitous octamer binding nuclear protein to bind a gamma-globin promoter fragment containing the mutated sequence; however, the ability of two erythroid specific proteins to bind the same fragment is increased three to five fold. DMS interference and binding experiments with mutated fragments indicate that the ubiquitous protein recognizes the octamer sequence, while the erythroid specific proteins B2, B3 recognize flanking nucleotides. Competition experiments indicate that protein B2 corresponds to an erythroid-specific protein known to bind to a consensus GATAG sequence present at several locations in alpha, beta and gamma-globin genes. Although the distal CCAAT box region of the gamma-globin gene shows a related sequence, an oligonucleotide including this sequence does not show any ability to bind the above mentioned erythroid protein; instead, it binds a different erythroid specific protein, in addition to a ubiquitous protein. The -117 G----A mutation also known to cause HPFH, and mapping two nucleotides upstream from the CCAAT box, greatly decreases the binding of the erythroid-specific, but not that of the ubiquitous protein, to the CCAAT box region fragment.

Base Sequence↗
PubMed1988

Sardinian G gamma-HPFH: a T----C substitution in a conserved "octamer" sequence in the G gamma-globin promoter.

A survey of hemoglobinopathies in Northern Sardinia allowed the identification of two subjects heterozygous for a new type of G gamma hereditary persistence of fetal hemoglobin (HPFH). The G gamma-globin gene from the HPFH chromosome shows the presence of a T----C substitution 175 nucleotides upstream of the CAP site, adding a new example of single-point mutations occurring in the promoter region of the gamma-globin genes and linked to HPFH phenotypes. In this case the mutation affects the 3' end nucleotide of a conserved octamer sequence known to be present in other regulatory elements of several genes.

Base Sequence↗
PubMed1987

The 3' ends of the deletions of Spanish delta beta zero-thalassemia and black HPFH 1 and 2 lie within 17 kilobases.

Spanish delta beta zero-thalassemia, a mild thalassemic condition characterized by increased level of hemoglobin (Hb) F production during adult life, is known to be due to a large deletion starting within the beta globin gene cluster and extending beyond the 3' breakpoint of any other similar deletional defects so far identified. By molecular cloning and by genomic mapping we now demonstrate that the deletion of Spanish delta beta zero-thalassemia ends at approximately 11 and 17 kilobases (kb) downstream to the 3' endpoints of black hereditary persistence of fetal hemoglobin (HPFH) type 1 and 2, respectively. As suggested by the complete characterization of this and other deletional defects involving the beta globin gene cluster, the 5' and 3' breakpoints of several deletions cluster in rather restricted DNA areas, further strengthening the idea that common molecular mechanisms may operate in causing these deletions.

Base Sequence↗
PubMed1976

[Unusual localization of an abdominal dermoid cyst].

A case of epidermoid cyst with rather unusual localization is reported. The cyst ran from the rear cavity of the omentum, penetrating between the leaves of the mesentery rott as far as the angle formed by the caecum and the final ansa before returning along the last ansa for about 20 cm, and compressing it to the point of creating an acute occlusive syndrome. Photographs and radiographs of the case are presented.

Abdominal Neoplasms↗