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P Izzo

Publications and source records attributed to P Izzo.

At least 55 records · Page 3Linked to original sources
PubMed1990

Characterization of the transcription-initiation site and of the promoter region within the 5' flanking region of the human aldolase C gene.

Several aldolase C clones from a human genomic library have been identified using a mouse aldolase C cDNA as a hybridization probe. The most complete fragment of the clones identified is 14 kb long and contains the complete aldolase C gene. The nucleotide sequence analysis of more than 5 kb includes the intron/exon organization structure of the gene and the 3' and 5' flanking regions. Although no human cDNA is yet available, a canonical polyadenylation signal at the 3' end of the gene indicates the proximity of the poly(A) addition site. We have analyzed the 5' noncoding region by S1 mapping and primer-extension experiments. The transcription-initiation sites for the human aldolase C gene in brain tissue was located about 1300 bp upstream from the methionine initiation codon. Preliminary functional assays of the promoter by transfection into rat glioma cells have indicated that promoter elements lie between positions -161 and -416 from the start point of transcription.

Amino Acid Sequence↗
PubMed1990

[Endoscopic papillotomy today. Indications and results].

The therapeutic possibilities offered by endoscopic papillotomy have improved in comparison with the recent past by virtue of mounting experience and increasingly satisfactory results. The position of the surgeon in the face of this procedure is more serene and objective than those who concern themselves with the endoscopic method as such. In long-term personal experience, endoscopic papillotomy was indicated in 162 cases of biliary lithiasic pathology--associated and otherwise with Odditis--and angiocolitis, with and without the gall-bladder. The reference to endoscopic treatment was mainly confined to patients with associated pathologies, dependent and otherwise, that involved general or specific surgical risk, while evaluations of the lumen of the biliary excretory way, of the coexistence of more or less incisive biliary inflammation, of the age of the patient--all parameters to which are attributed special importance for the choice between derivative intervention and open papillotomy--do not possess particular significance for the endoscopic method. Results obtained and the low incidence of short and long-term morbility support the claim to absolute usefulness of the method when it is proposed on correct indications and carried out with expert technique.

Ampulla of Vater↗
PubMed1989

In vivo activity of the most proximal promoter of the human aldolase A gene and analysis of transcriptional control elements.

The genomic region upstream from exon F (exon IV) of the human aldolase A gene has been studied for its ability to direct the transcription of a reporter gene in vivo. Transfection experiments in human hepatoma cells (Hep 3B) followed by CAT assay, and S1 mapping analysis, demonstrated that: (i) this region is able to drive CAT gene transcription; (ii) all the transcriptional control elements of this promoter are downstream from nucleotide -384 of the longer ubiquitous RNA start site and the sequences between -384 and -262 play a crucial role in transcriptional efficiency; (iii) initiation starting points for two mRNAs exist 61 bp apart. Gel retardation and footprinting assays demonstrated the presence of DNA-protein complexes mainly in the region between -384 and -262 and such ubiquitous binding factors as Sp1 and AP-1.

Base Sequence↗
PubMed1988

Human aldolase A gene. Structural organization and tissue-specific expression by multiple promoters and alternate mRNA processing.

The complete nucleotide sequence of the human aldolase A isoenzyme gene is reported. The cloned gene sequence, spanning 7530 bp, includes twelve exons and occurs as a single copy per haploid human genome. The structural organization of the gene is quite complex: eight exons containing the coding sequence are common to all mRNAs extracted from human and other mammalian sources; four additional exons are present in the 5' untranslated region, of these one is contained in the ubiquitous type of mRNA, the second is in the muscle-specific type of mRNA and the third and fourth are in a minor species of mRNA found in human liver tissue. Furthermore, the determined sequence includes 1000 nucleotides upstream from the first exon (exon I) in the 5' flanking region, and 400 nucleotides, which include the polyadenylation signal, downstream from the termination codon. S1-nuclease-protection analysis of the 5' end of mRNA extracted from human cultured fibroblasts, muscle and hepatoma cell lines indicates the existence of four different transcription-initiation sites. The latter are also supported by the presence of conventional sequences for eukaryotic promoters. Therefore, the four promoters on the same gene generate different tissue-specific transcripts, which share the translated sequence, but each has a unique 5' untranslated region as a result of differential mRNA processing. The nucleotide homology at the coding region and the intron-exon organization of the three human and mammalian aldolase A, B and C genes confirm that they arose from a common ancestral gene, and that aldolase B diverged first.

Base Sequence↗
PubMed1987

A new human species of aldolase A mRNA from fibroblasts.

A full-length cDNA aldolase A clone was isolated from a human fibroblast cDNA library and completely sequenced. Excluding the poly(A) tail, the clone covers 1095 base pairs (bp) of the coding region, plus 199 bp downstream for the termination codon and 146 bp upstream for the initiation codon, within a total of 1440 bp. Primer extension experiments performed with human cultured fibroblast mRNA indicate an elongated product of a further 40 bp. These results evaluated together with those obtained in a concurrent study concerning aldolase A mRNA isolated from human liver are direct evidence of aldolase A mRNA multiplicity in man. The data also suggest the existence in mammals of three different classes of aldolase A mRNA, which would account for tissue specificity and resurgence of foetal expression in tumors.

Amino Acid Sequence↗
PubMed1986

Structure and expression of mouse aldolase genes. Brain-specific aldolase C amino acid sequence is closely related to aldolase A.

Brain-specific aldolase C amino acid sequence (greater than 75% of the coding region) was determined for the first time. Two cDNA clones, pAM1 and pAM2, were identified, from a mouse brain library, by using human aldolase B cDNA as a probe. The larger one, pAM2, identified as a cDNA for aldolase C, has been completely sequenced and covers the 5'-untranslated region of the mRNA and the codons for amino acids 1-227 of the protein. The sequence indicates that aldolase C is more akin to aldolase A than to aldolase B. A cDNA library from mouse muscle was also screened, allowing the identification of clones pAM3 and pAM4, which contain cDNAs for aldolase A. The sequence obtained from pAM3 covers 70% of the coding sequence (amino acids 99-355) from the -COOH part of the protein. The cDNAs for the three aldolases, A, B and C, have been hybridized to RNA from various rat tissues. The results confirm the tissue specificity of the expression of the mRNA for the different isoenzymes and support the hypothesis that aldolase C expression, as aldolase A and B, is regulated at the transcriptional level or, in any case, via mRNA concentration.

Amino Acid Sequence↗
PubMed1986

Italian type of deletional hereditary persistence of fetal hemoglobin.

We report a new type of deletion of the beta globin gene cluster in the Italian population that confers a phenotype of hereditary persistence of fetal hemoglobin (HPFH) to the carriers. This deletion begins approximately 5 kilobases (kb) 5' to the delta globin gene and ends approximately 30 kb 3' to the beta globin gene, in close proximity to the 3' end of an Indian HPFH. In all four previously described HPFH, a repetitive Alu I region 5' to the delta globin gene is largely or completely deleted; the 5' end of the new HPFH is consistent with this common feature. In addition, the finding that Italian and Indian HPFHs, as reported for other groups of deletions, have very close 3' ends, strengthens the idea that common mechanisms may operate in generating these deletions. Finally, we show that, in spite of similar 5' breakpoints, the deletion of Spanish delta beta(0)-thalassemia is at least 8 kb longer than that of Negro HPFH type I, thus ruling out the hypothesis that the overall extent of the deletion might influence the level of gamma globin chain synthesis.

Chromosome Deletion↗
PubMed1984

Isolation and nucleotide sequence of a full-length cDNA coding for aldolase B from human liver.

Two recombinant clones, pA2 and pA3, containing cDNA sequences for human aldolase B have been isolated from a full length human liver cDNA library. The larger one, pA3, has been subcloned in M13 phage and completely sequenced with the chain terminator method. The sequence covers 1,600 nucleotides including the whole coding region (1,050 nucleotides), 67 nucleotides from the 5' non-coding region and the whole 3' non-coding region, 440 nucleotides long, down to the poly-A tail. Comparison with rabbit aldolase A and with a partial sequence of rat aldolase B, shows a homology of about 76% for aldolase A and of about 94% for aldolase B, which indicates that the sequenced cDNA codes for the liver isoenzyme. This is the first complete sequence reported for human aldolase B. The pA3 clone strongly hybridizes to 18S mRNA from human adult liver as expected from the size of the isolated cDNA.

Amino Acid Sequence↗
PubMed1983

Cloning of several cDNA segments coding for human liver proteins.

A human cDNA library was constructed using M13 derivative vectors. The simple and rapid procedures for sequencing single-stranded DNA by the dideoxy chain termination method allowed a screening of individual clones directly by DNA sequence analysis. Some of these clones were identified as coding for: serum albumin, alpha1-antitrypsin, retinol-binding protein, prothrombin, haptoglobin, and metallothionein. Furthermore, a clone coding for aldolase B was tentatively identified on the basis of high sequence homology with rabbit muscle aldolase.

Amino Acid Sequence↗
PubMed1982

[Fetal glucose regulation: glycosylated hemoglobin in cord blood].

Glycosylated haemoglobins were assayed at delivery in 64 pregnant women (48 normals and 16 diabetics) in maternal and cord blood with the colorimetric method of Fluckigër and Winter-halter. A good correlation was observed between maternal and funicular glycosylated Hb (r = 0.67, p less than 0.001) in normal subjects; there wasn't any significant correlation in diabetic pregnant; (r = 0.29). Maternal glycosylated haemoglobins were compared to Schlichkrull's M of glycemic cycles in diabetic pregnant all these subjects showed a good glycemic regulation. Colorimetric technique can separate glycosylated haemoglobins from Hb F, and so allows their detection in cord blood. Glycosylated haemoglobin's assay in cord blood at delivery is an index of fetal glycoregulation in the last trimester of pregnancy and it represents a parameter of fetal pancreatic insulin incretion during intrauterine growth.

Blood Glucose↗
PubMed1982

Molecular comparison of delta beta-thalassemia and hereditary persistence of fetal hemoglobin DNAs: evidence of a regulatory area?

The hematological phenotypes of several Mediterranean patients with delta beta-thalassemia and hereditary persistence of fetal hemoglobin have been characterized. Although clinical and hematological characteristics are essentially superimposable in all heterozygous delta beta-thalassemics, these patients show typical G gamma/A gamma ratios in their Hb F, ranging from approximately 0.07 in Sardinian to approximately 0.15 in Sicilian and approximately 0.35 in Spanish patients. A gamma Sardinian-(isoleucine-75 leads to threonine) is found in Spanish patients and accounts for all of the A gamma production in heterozygotes, indicating that persistent production of gamma chains occurs cis to the delta beta-thalassemia gene. The molecular heterogeneity of these conditions is demonstrated by restriction enzyme mapping of DNA; Sicilian and Calabrian patients show a deletion starting from the delta-globin intron and extending several kilobases 3' to the beta-globin gene; in Spanish patients the deletion starts approximately 2-3 kilobases 5' to the delta-globin gene and extends well beyond the beta-globin gene. Comparison of these deletions with previously described ones in Negro and in a new Southern Italian case of hereditary persistence of fetal hemoglobin suggests that the deletion of a region centered at a cluster of repetitive sequences approximately 3.5 kilobases 5' to the delta-globin gene may be critical for the persistent expression of high levels of gamma-globin in hereditary persistence of fetal hemoglobin compared to delta beta-thalassemia. The concept that the deletion or mutation of specific areas (rather than nonspecific changes brought about by large deletions in the globin cluster) is important in determining the persistent expression of gamma-globin genes is supported by the finding of a nondeletion type of delta beta-thalassemia in Sardinians.

Chromosome Deletion↗
PubMed1981

Purification and properties of several transfer RNA methyltransferases from S. typhimurium.

A fast method for a single-step fractionation of a number of tRNA methyltransferases from Salmonella typhimurium is described. The method basically consists of ion-exchange chromatography on a phosphocellulose column and permits the separation of the enzymes forming mt6A, m1G, m5U, m7G. The enzyme fractions appear sufficiently purified to allow the estimation of some molecular and kinetic properties. The apparent KM for adenosylmethionine range between 1.5 to 3.2 X 10(-5) M, whereas KM for undermethylated tRNA range between 3.1 X 10(-5) M to 3.1 X 10(-4) M. Glycerol gradient determination indicates the following Mr for the native proteins: 25 X 10(3), 40 X 10(3), 50 X 10(3) and 65 X 10(3) for m7G-, mt6A-, m1G- and m5U-forming enzymes, respectively. A complete analysis of methylated nucleosides formed in vivo in S. typhimurium has been obtained: it also allowed us to infer the pattern of the various tRNA methyltransferases for this prokaryote. The tRNA methyltransferase forming mt6A has been isolated for the first time from any type of cell.

Chromatography, Ion Exchange↗
PubMed1979

[Biochemical and clinical studies of 2 new Italian cases of Hb G-Ferrara heterozygosis].

The Authors report the data concerning a family coming from Ficarolo (Rovigo). The father and one son were found hematologically healthy, but resulted carriers of Hb G-Ferrara. This is an unstable rare pigment with a replacement in the beta 57 (E-1) helicoidal position. The type and site of the mutation explain the "in vitro" molecular instability; on the other hand, this latter doesn't seem to cause any hematological disorder, even if an increased met-Hb production was found when affected blood was incubated at 37 degrees C for two hours in sterile conditions.

Adult↗