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G Gadaleta

Publications and source records attributed to G Gadaleta.

At least 19 recordsLinked to original sources
PubMed2005

Study of the mitochondrial transcription factor A (Tfam) gene in the primate Presbytis cristata.

The mitochondrial transcription factor A (Tfam) is a member of the HMG-box protein family, necessary for both transcription and maintenance of mitochondrial DNA. The gene is structured in seven exons and six introns and it is estimated to span about 10 kb in mouse, human and rat. In addition to the full length mRNA of Tfam, a shorter mRNA isoform lacking exon 5 has been found to be widely distributed in human and rat tissues. Here we present the isolation and characterization of Tfam gene in the primate Presbytis cristata which belongs to the Cercopithecidae family. We have determined the complete CDS sequence, the size of all the six introns, the complete sequences of the three shorter ones (I, III, VI) and the partial sequences of the long introns (II, IV, V). The comparison with other available Tfam sequences from mammals has revealed a high degree of conservation (above 90%) both in CDS and introns. By in situ hybridization (FISH) experiments we have mapped Tfam gene on chromosome 12 which, according to other cytogenetics studies, is the homologous region of chromosome 10, where human Tfam has been mapped. Moreover we have searched for the presence of alternatively spliced isoforms through several approaches, such as RT-PCR and differential hybridization. In Presbytis cristata we have not detected the presence of any spliced isoforms lacking exons; however we have identified one isoform in which part of the intron I is retained in the mRNA. The inclusion of this portion of intron I would originate an early stop codon if translated.

Alternative Splicing↗
PubMed2004

Metabolic variations with oral antidiabetic drugs in patients with Type 2 diabetes: comparison between glimepiride and metformin.

Patients with Type 2 diabetes (T2DM) are at high risk of morbidity and mortality from cardiovascular complications, and hypoglycaemia increases this risk. Furthermore, other metabolic parameters exacerbate cardiovascular risk in these patients. The aim of the study was to compare the metabolic effects of glimepiride and metformin in patients with T2DM. We evaluated 164 patients with T2DM (80 males, 84 females) in a multicentre, randomised, controlled, open, parallel group study comparing glimepiride with metformin. Eighty-one patients (aged 56+/-10 yr) received glimepiride (3+/-1 mg/d); 83 patients (aged 58+/-9 yr) received metformin (2500+/-500 mg/d). Patients had been diagnosed for < or = 6 months; they were non-smokers; had no hypertension or coronary heart disease; were not taking hypolipidaemic drugs, diuretics, beta-blockers or thyroxin; and had normal renal function. Metabolic parameters were measured after 6 and 12 months of treatment. Glimepiride significantly lowered lipoprotein(a) [Lp(a)] and homocysteine levels (HCT) at 6 and 12 months. Both glimepiride and metformin lowered plasminogen activator inhibitor Type 1 (PAI-1) at 12 months and significantly improved levels of glycosylated haemoglobin, fasting plasma glucose and post-prandial plasma glucose after 6 and 12 months. Metformin significantly lowered fasting plasma insulin and postprandial plasma insulin. Glimepiride and metformin also reduced levels of other metabolic parameters in patients with T2DM. In particular, glimepiride significantly reduced HCT, Lp(a), and PAI-1 levels, important metabolic risk factors for atherosclerotic vascular disease. These reductions may be owing to improved glucose metabolism, but it cannot be excluded that these drugs have a direct effect on additional metabolic parameters.

Aged↗
PubMed1999

The 25 kDa protein recognizing the rat curved region upstream of the origin of the L-strand replication is the rat homologue of the human mitochondrial transcription factor A.

Mass spectrometry matrix-assisted laser desorption ionization (MALDI) analysis and N-terminus sequencing as well as immunoblotting experiments using human and mouse antibodies have allowed us to identify the 25 kDa protein, previously isolated from rat liver using magnetic beads coated with a rat liver mitochondrial (mt) DNA region upstream of the Ori-L, as the homologue of human mt transcription factor A (mtTFA). We can therefore identify this DNA binding protein as the rat mtTFA. Furthermore, since we previously showed that the 25 kDa protein purified from rat liver was able to bind the curved mtDNA region upstream of the Ori-L as well as the curved mtDNA in the D-loop region, the results here reported lead us to state, for the first time, that mtTFA binds both the curved regions of mtDNA upstream of the two replication origins.

Amino Acid Sequence↗
PubMed1997

In organello footprinting analysis of rat mitochondrial DNA: protein interaction upstream of the Ori-L.

An in organello footprinting approach has been used to probe a protein-DNA interaction of a nuclear coded 25 kDa protein, previously isolated in our laboratory, that binds "in vitro" a region within the ND2 gene, located upstream of the Ori-L. Footprinting studies with the purine-modifying reagent dimethyl sulfate and the pirimidine-modifying reagent potassium permanganate were carried out in isolated mitochondria from rat liver. Dimethyl sulfate footprinting has allowed the detection of a protein-DNA interaction within the curved ND2 region with contact sites located in both the strands. Potassium permanganate footprinting allowed detection of an adjacent permanganate-reactive region. We hypothesize that the permanganate-reactive region is a single stranded DNA due to a profound helix distortion induced by a 25 kDa protein binding to the nearest region.

Animals↗
PubMed1996

Isolation of a 25-kDa protein binding to a curved DNA upstream the origin of the L strand replication in the rat mitochondrial genome.

The presence of a curved DNA sequence in the gene for the NADH-dehydrogenase subunit 2 of rat mitochondrial genome, upstream from the origin of the light strand replication have been demonstrated through theoretical analysis and experimental approaches. Gel retardation assays showed that this structure makes a complex with a protein component extracted from the mitochondrial matrix. The isolation and purification of this protein is reported. With a Sepharose CL-6B and magnetic DNA affinity chromatography a polypeptide was purified to homogeneity having 25-kDa mass as shown by gel electrophoresis. To functionally characterize this protein, its capability to bind to other sequences of the homologous or heterologous DNA and to specific riboprobes was also investigated. A role for this protein as a trans-acting agent required for the expression of the mammalian mitochondrial genome is suggested.

Animals↗
PubMed1995

A 67-kDa protein binding to the curved DNA in the main regulatory region of the rat mitochondrial genome.

We have purified, by sequence-specific affinity chromatography, a mitochondrial (mt) matrix protein which binds to the curved DNA located between the replication origin (ori) of the leading strand (ori-H) and the two transcription promoters in the rat mt genome. The protein was characterized by gel electrophoresis as a 67-kDa polypeptide and seems to be involved in the DNA contact on the mt light strand. This protein differs (in the size and location of its DNA-binding site) from other DNA-binding proteins studied so far in animal mt systems. We suggest a role for the 67-kDa protein, assisted by other proteins, in regulating the initiation of leading-strand replication.

Animals↗
PubMed1992

[Complications and sequelae of cardiac electrostimulation in children. Our experience with 47 children].

Permanent cardiac pacing is now easily feasible in children and even in small infants, but the long-term results of this procedure are not well known. We analyzed our experience to determine the morbidity of pacing in children. Over the past 10 years, 47 pediatric patients (pts) required pacemaker implantation in our institution. The mean age was 8.3 +/- 4 years (1 day-17 years) and mean body weight was 23 +/- 14 Kg (2.2-60 Kg). 25 pts had heart disease. 40 children had an A-V block (congenital in 22 cases, post-operative in 17 pts, and secondary to a systemic disease in 1 case); 7 pts had a sick sinus syndrome, primitive in 4 and postoperative in 3 cases. The first pacemaker implantation was epicardial in 17 and transvenous in 30 pts. The pacing was single-chamber in 45 pts (VVI 32, VVIr 7, AAI 5, AAIr 1) and dual-chamber in 2 pts (DDD 1, VDD 1). Two newborns, both with a congenital A-V block and severe heart failure, died in the first hours after epicardial pacing. Two other children, both with congenital heart disease, died during follow-up, but the death was not pacemaker-related. Finally, two children were lost to follow-up. The mean follow-up of the 41 remaining pts was 5.2 +/- 3.5 years (4 months-10 years). Twelve children (29%) required 19 implant revisions and the causes were: lead fracture (26%), rising stimulation threshold (26%), growth problems (21%), erosion and/or pocket infection (21%). Revisions were more common in epicardial (52%) than in endocardial (22%) implantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Sequence-dependent DNA curvature: conformational signal present in the main regulatory region of the rat mitochondrial genome.

Theoretical analysis and experimental approaches by gel electrophoresis in retarding conditions allowed us to identify the presence of an intrinsic bending in the D-loop containing region of the rat mitochondrial genome. The curvature was located in the right domain of the sequence analyzed, between the origin of replication of the heavy strand and its promoter. The preliminary evidence of a specific recognition of the bent DNA with mitochondrial matrix proteins suggests a probable role of this DNA conformation in the duplication and/or expression of the mammalian mitochondrial genome.

Animals↗
PubMed1989

The complete nucleotide sequence of the Rattus norvegicus mitochondrial genome: cryptic signals revealed by comparative analysis between vertebrates.

This paper reports the nucleotide sequence of rat mitochondrial DNA, only the fourth mammalian mitochondrial genome to be completely sequenced. Extensive comparative studies performed with similar genomes from other organisms revealed a number of interesting features. 1) Messenger RNA genes: the codon strategy is mainly dictated by the base compositional constraints of the corresponding codogenic DNA strand. The usage of the initiation and termination codons follows well-established rules. In general the canonical initiator, ATG, and terminators, TAA and TAG (in rat, only TAA), are always present when there is gene overlapping or when the mRNAs possess untranslated nucleotides at the 5' or 3' ends. 2) Transfer RNA genes: a number of features suggest the peculiar evolutionary behavior of this class of genes and confirm their role in the duplication and rearrangement processes that took place in the evolution of the animal mitochondrial genome. 3) Ribosomal RNA genes: accurate sequence analysis revealed a number of significant examples of complementarity between ribosomal and messenger RNAs. This suggests that they might play an important role in the regulation of mitochondrial translation and transcription mechanisms. The properties revealed by our work shed new light on the organization and evolution of the vertebrate mitochondrial genome and more importantly open up the way to clearly aimed experimental studies of the regulatory mechanisms in mitochondria.

Amino Acid Sequence↗
PubMed1987

[Role of ambulatory ECG in the diagnostic work of a cardiology division].

Holter monitoring may be effected during hospitalization either for clinical research or for high-risk patients or after surgical treatments. In the other cases, if possible, it should be better to effect ambulatory electrocardiographic monitoring in patients engaged in their normal daily activity nevertheless reducing hospital costs. Last year, in our department we effected 2420 Holter monitoring, of which 44% for patients hospitalized in our department, 11% hospitalized in other divisions, 44% for ambulatory patients. Holter monitoring was effected in the 35% of patients to detect arrhythmias, in the 29% for the evaluation of the effect of antiarrhythmic therapy; the 28% of Holter monitoring was recorded for patients recovering from acute infarction. Holter monitoring, associated to the other cardiological screening tests, has a very important rule for diagnosis of arrhythmias or myocardial ischemia, prognostic evaluation of cardiopathic patients (ischemic heart disease, cardiomyopathies, valvular and congenital heart disease), verification of the effects of therapy (PTCA, surgical and antiarrhythmic treatment).

Arrhythmias, Cardiac↗
PubMed1986

Structural conservation and variation in the D-loop-containing region of vertebrate mitochondrial DNA.

The nucleotide sequences of the D-loop-containing regions of three rat mitochondrial DNAs (mtDNAs), two from the species Rattus norvegicus and one from R. rattus, were determined. Comparisons made among these sequences and with the mouse sequence showed that, on the basis of both base composition and frequency of nucleotide alterations, three domains could be defined within the D-loop-containing region: a central conserved segment, poor in L-strand adenine, flanked by two divergent, adenine-rich regions. Deletions and insertions were found to occur at an unexpectedly high frequency in these sequences and the conserved sequence block called CSB-1 was found not to be intact in the R. rattus sequence. Although in comparisons of more distantly related mtDNAs the D-loop region is the most divergent on the molecule, it does not diverge more than typical protein genes between R. norvegicus and R. rattus, and its central conserved domain appears to be one of the molecule's most conserved regions. The most variable domain borders the tRNAPhe gene and contains the L and H-strand promoters and the 5' terminus for H-strand DNA synthesis. Within this region we have found sequences in all the mtDNAs we have examined, including those of human, two artiodactyls and Xenopus, that are capable of folding into cloverleaf structures. In the other divergent domain of the same mtDNAs, we find sequences capable of assuming similar secondary structural configurations at or near the sites for the termination of D-loop DNA synthesis. The evolutionary preservation of the potential to form such structures despite the high primary-structural divergence of the regions they occur in, suggests the structures are of principal importance for some processes occurring in the D-loop-containing region.

Animals↗
PubMed1983

Non-random patterns of nucleotide substitutions and codon strategy in the mammalian mitochondrial genes coding for identified and unidentified reading frames.

The base sequence of large part of the mitochondrial DNA of Wistar rats is presented. The sequence is compared with those of other mammalian mitochondrial DNAs. The nucleotide and amino acid homologies, codon strategy, nature and patterns of substitutions are reported. It results a very high amount of silent substitutions and, in short divergence time, a predominance of transitions on transversions. In both types of substitutions a strong bias in avoiding the use of the G in the third codon position is observed.

ATP Synthetase Complexes↗
PubMed1982

The nucleotide sequences of several tRNA genes from rat mitochondria: common features and relatedness to homologous species.

We have determined the nucleotide sequences of thirteen rat mt tRNA genes. The features of the primary and secondary structures of these tRNAs show that those for Gln, Ser, and f-Met resemble, while those for Lys, Cys, and Trp depart strikingly from the universal type. The remainder are slightly abnormal. Among many mammalian mt DNA sequences, those of mt tRNA genes are highly conserved, thus suggesting for those genes an additional, perhaps regulatory, function. A simple evolutionary relationship between the tRNAs of animal mitochondria and those of eukaryotic cytoplasm, of lower eukaryotic mitochondria or of prokaryotes, is not evident owing to the extreme divergence of the tRNA sequences in the two groups. However, a slightly higher homology does exist between a few animal mt tRNAs and those from prokaryotes or from lower eukaryotic mitochondria.

Animals↗