Enhanced Risk Stratification for Children and Young Adults with B-Cell Acute Lymphoblastic Leukemia: A Children's Oncology Group Report

Current strategies to treat pediatric acute lymphoblastic leukemia rely on risk stratification algorithms using categorical data. We investigated whether using continuous variables assigned different weights would improve risk stratification. We developed and validated a multivariable Cox model for relapse-free survival (RFS) using information from 21199 patients. We constructed risk groups by identifying cutoffs of the COG Prognostic Index (PICOG) that maximized discrimination of the predictive model. Patients with higher PICOG have higher predicted relapse risk. The PICOG reliably discriminates patients with low vs. high relapse risk. For those with moderate relapse risk using current COG risk classification, the PICOG identifies subgroups with varying 5-year RFS. Among current COG standard-risk average patients, PICOG identifies low and intermediate risk groups with 96% and 90% RFS, respectively. Similarly, amongst current COG high-risk patients, PICOG identifies four groups ranging from 96% to 66% RFS, providing additional discrimination for future treatment stratification. When coupled with traditional algorithms, the novel PICOG can more accurately risk stratify patients, identifying groups with better outcomes who may benefit from less intensive therapy, and those who have high relapse risk needing innovative approaches for cure.

Effects of Nordic walking in Alzheimer's disease: A single-blind randomized controlled clinical trial

Non-pharmacological approaches, including exercise programs, have been proposed to improve cognitive function and behavioral symptoms, such as depression, agitation, or aggression, in the management of patients with Alzheimer's disease (AD). Indeed, physical inactivity is one of the main modifiable risk factors in patients with AD, as well as in the development of cardiovascular diseases and related pathologies. Although Nordic Walking (NW), a particular type of aerobic exercise, is known to benefit the health of aging populations, there is little evidence that patients with AD may benefit from this non-pharmacological treatment. In this context, we performed a pilot study in 30 patients with mild/moderate AD to evaluate whether NW influences different cognitive domains, including executive functions, visual-spatial abilities, and verbal episodic memory. To this aim, 15 patients (Control group, CG) underwent reality orientation therapy, music therapy, motor, proprioceptive and postural rehabilitation, and 15 patients (experimental group, EG) in addition to the activities performed by the CG also had the NW with a frequency of twice a week. Neuropsychological assessments and evaluations of daily activities and quality of life were performed at baseline and after 24 weeks. Twenty-two patients, including 13 in the CG and nine in the EG completed the activity program after 24 weeks. The EG showed a significant improvement in the Frontal Assessment Battery, Rey's auditory Verbal Learning Test Delayed Recall, Raven's Colored Progressive Matrices, and completion time for the Stroop Word-Color Interference test, compared to the CG. NW was able to improve cognitive domains like visual-spatial reasoning abilities, verbal episodic memory, selective attention, and processing speed in AD patients. These results, if confirmed by further studies with a larger number of patients and a longer training period, may prospect NW as a safe and likely useful strategy to slow down cognitive impairment in mild/moderate AD.

Molecular characterization of two sub-family specific monoclonal antibodies to meningococcal Factor H binding protein

Factor H binding protein (FHbp) is a component of two licensed vaccines for prevention of sepsis and meningitis caused by serogroup B meningococci. FHbp binds human Factor H (FH), which contributes to evasion of host immunity and FHbp sequence variants can be classified into two sub-families. Antibodies against FHbp elicit complement-mediated killing and can inhibit recruitment of FH to the bacterial surface. We report epitope mapping studies of two murine IgG mAbs, designated JAR 31 and JAR 36, isolated from a mouse immunized with FHbp in sub-family A, which is present in ∼30-40% of invasive isolates. In the present study, we tested the reactivity of mAbs JAR 31 and JAR 36 with seven natural FHbp sequence variants from different phylogenic groups. We screened bacteriophage-displayed peptide libraries to identify amino acid residues contributing to the JAR 36 epitope. Based on the reactivities of mAbs JAR 31 and JAR 36 with the seven FHbp variants, and the frequent occurrences of aspartate (D) and lysine (K) residues in the JAR 36-bound phage peptides, we selected six residues in the carboxyl-terminal region of FHbp for replacement with alanine (A). The D201A and K203A substitutions respectively eliminated and decreased binding of mAbs JAR 31 and JAR 36 to FHbp. These substitutions did not affect binding of the control mAb JAR 33 or of human FH. JAR 31 or JAR 36 mediated cooperative complement-mediated bactericidal activity with other anti-FHbp mAbs. The identification of two amino acid residues involved in the epitopes recognized by these anti-FHbp mAbs may contribute to a more complete understanding of the spatial requirements for cooperative anti-FHbp mAb bactericidal activity.

Selection in the making: a worldwide survey of haplotypic diversity around a causative mutation in porcine IGF2

Domestic species allow us to study dramatic evolutionary changes at an accelerated rate due to the effectiveness of modern breeding techniques and the availability of breeds that have undergone distinct selection pressures. We present a worldwide survey of haplotype variability around a known causative mutation in porcine gene IGF2, which increases lean content. We genotyped 34 SNPs spanning 27 kb in 237 domestic pigs and 162 wild boars. Although the selective process had wiped out variability for at least 27 kb in the haplotypes carrying the mutation, there was no indication of an overall reduction in genetic variability of international vs. European local breeds; there was also no evidence of a reduction in variability caused by domestication. The haplotype structure and a plot of Tajima's D against the frequency of the causative mutation across breeds suggested a temporal pattern, where each breed corresponded to a different selective stage. This was observed comparing the haplotype neighbor-joining (NJ) trees of breeds that have undergone increasing selection pressures for leanness, e.g., European local breeds vs. Pietrain. These results anticipate that comparing current domestic breeds will decisively help to recover the genetic history of domestication and contemporary selective processes.

Augmented Berlin-Frankfurt-Muenster (ABFM) regimen for children with standard-risk acute lymphoblastic leukemia (SR-ALL) and slow early response (SER)

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Background: Numerous studies have shown that SER in ALL has a negative impact on outcome. Children's Cancer Group CCG-1882 demonstrated that post-induction intensification greatly improved the outcome of children with high-risk ALL and SER. Five year event-free-survival (EFS), and overall survival (OS) for the augmented regimen was 75 ± 4% vs 55 ± 4.5%, and 78 ± 4% vs 67 ± 5% for the standard regimen, p <0.001 and 02 respectively (N Engl J Med 1998; 338:1663–71). Methods: Therefore, COG-1952 and COG- 1991, studies for patients with SR-ALL, assigned the slow early responders to augmented therapy, while others were randomized according to the study design. Study eligibility criteria were similar for both, and included newly diagnosed children with National Cancer Institute SR criteria. COG-1952 accrued a total of 2,027 patients and COG-1991 accrued 3,054. In COG-1952 patients were deemed SER if their day-7 marrow had >5% blasts, and their day-14 marrow >25%. COG-1991 used the same criteria for SER, but also added patients whose day-7 marrow had >25% blasts and their day-14 marrow had >5% blasts to the SER group. This was based on the unfavorable outcome of this subgroup in COG-1952. The augmented therapy in COG-1991 like the CCG-1882 and COG-1952, was based on a COG-modified ABFM, but differed in using dexamethasone as the sole steroid and pegylated asparaginase as the asparaginase preparation, as compared to prednisone in induction and maintenance, and native E coli asparaginase. Results: Comparative groups with days 7 and 14 M3 marrows and unfavorable cytogenetics included 126 patients from COG-1991 and 81 from the COG-1952 were assigned to their corresponding ABFM regimens. Four year EFS and OS were 85% ± 5% and 90 ± 4% for CCG-1991 vs 61 ± 5.6% and 75 ± 5% for CCG-1952, p = 0.003 and 0.04 respectively. Conclusion: We conclude that the use of dexamethasone, and pegylated asparaginase greatly improves the outcome of children with NCI-SR with SER treated on a modified augmented BFM therapy, thus supporting the use of these agents in ALL therapy.

No significant financial relationships to disclose.

SNP-based markers for discriminating olive (Olea europaea L.) cultivars

A set of 11 polymorphic markers (1 cleaved amplified polymorphic sequence (CAPS), 2 sequence-characterized amplified regions (SCARs), and 8 single-nucleotide polymorphism (SNP)-derived markers) was obtained for olive cultivar identification by comparing DNA sequences from different accessions. Marker development was more efficient, using sequences from the database rather than cloning arbitrary DNA fragments. Analyses of the sequences of 3 genes from 11 diverse cultivars revealed an SNP frequency of 1 per 190 base pairs in exons and 1 per 149 base pairs in introns. Most mutations were silent or had little perceptible effect on the polypeptide encoded. The higher incidence of transversions (55%) suggests that methylation is not the major driving force for DNA base changes. Evidence of linkage disequilibrium in 2 pairs of markers has been detected. The set of predominantly SNP-based markers was used to genotype 65 olive samples obtained from Europe and Australia, and was able clearly to discriminate 77% of the cultivars. Samples, putatively of the same cultivar but derived from different sources, were revealed as identical, demonstrating the utility of these markers as tools for resolving nomenclature issues. Genotyping data were used for constructing a dendrogram by UPGMA cluster analysis using the simple matching similarity coefficient. Relationships between cultivars are discussed in relation to the route of olive's spread.

Characterization and genotyping of the caprine kappa-casein variants

Kappa-Casein (kappa-CN) is the milk protein that determines the size and specific function of milk micelles, and its cleavage by chymosin is responsible for milk coagulation. We have previously detected and characterized four variants of the goat kappa-CN in Spanish, French, and Italian breeds by screening the major part of the coding region in exon 4. Here we have sequenced and analyzed the full coding region of the kappa-CN gene which includes exons 3 and 4. No additional mutations were found, with exception of a single nucleotide substitution in exon 3, which had no amino acid change. However, the analysis of the association between the different mutations resulted in two new variants designated kappa-CN F and G. The novel variants are present in the Italian breeds Teramana, Girgentana, and Sarda (variant F). A protocol for rapid simultaneous genotyping of all known kappa-CN variants using the primer extension method was described, and a total of 210 animals from nine European breeds were genotyped. Alleles A and B are the most frequent variants occurring in the majority of breeds with highest prevalence of the B variant, except for the Canaria breed where the A allele is more frequent. Sequence data suggest that the F variant is the original type of caprine kappa-CN, other alleles being derived from this type following two different trunks by successive mutations.

A first linkage map of olive (Olea europaea L.) cultivars using RAPD, AFLP, RFLP and SSR markers

The first linkage map of the olive (Olea europaea L.) genome has been constructed using random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphisms (AFLP) as dominant markers and a few restriction fragment length polymorphisms (RFLP) and simple-sequence repeats (SSR) as codominant markers. Ninety-five individuals of a cross progeny derived from two highly heterozygous olive cultivars, Leccino and Dolce Agogia, were used by applying the pseudo test-cross strategy. From 61 RAPD primers 279 markers were obtained - 158 were scored for Leccino and 121 for Dolce Agogia. Twenty-one AFLP primer combinations gave 304 useful markers - 160 heterozygous in Leccino and 144 heterozygous in Dolce Agogia. In the Leccino map 249 markers (110 RAPD, 127 AFLP, 8 RFLP and 3 SSR) were linked. This resulted in 22 major linkage groups and 17 minor groups with fewer than four markers. In the Dolce Agogia map, 236 markers (93 RAPD, 133 AFLP, 6 RFLP and 4 SSR) were linked; 27 major linkage groups and three minor groups were obtained. Codominant RFLPs and SSRs, as well as few RAPDs in heteroduplex configuration, were used to establish homologies between linkage groups of both parents. The total distance covered was 2,765 cM and 2,445 cM in the Leccino and Dolce Agogia maps, respectively. The mean map distance between adjacent markers was 13.2 cM in Leccino and 11.9 cM in Dolce Agogia, respectively. Both AFLP and RAPD markers were homogeneously distributed in all of the linkage groups reported. The stearoyl-ACP desaturase gene was mapped on linkage group 4 of cv. Leccino.

Short communication: characterization of a new genetic variant in the caprine kappa-casein gene

A new polymorphism has been identified in the goat kappa-casein gene by evaluating genomic DNA from the Montefalcone breed in Italy. The polymorphic site consists of a single nucleotide substitution A to G at position 242 of the exon 4 and produces an amino acid substitution Asp/Gly. A polymerase chain reaction-restriction fragment length polymorphism protocol for rapid genotyping of the variant has been developed, using the HaeIII enzyme. Animals from Italian, Spanish, and French breeds have been analyzed to investigate the occurrence of the allele in other populations. The allele appears to be exclusive to the Montefalcone breed.

[Continence problems after radical prostatectomy: role of rehabilitation of the pelvic floor]

Continence mechanisms can be compromised after radical prostatectomy. Relatively low percentages of urinary incontinence are reported (2-15%). Perineal floor physiotherapy is considered an actual method of treatment of urinary incontinence in females. It is based on pelvic floor muscles exercises, biofeedback and functional electrical stimulation. The aim of physiotherapy is to improve pelvic floor muscles proprioception, to increase tone of levator ani and to favour automatization of these muscles in daily life. The reports in Literature on perineal floor physiotherapy in treating incontinence after radical prostatectomy are scarce. In this paper we present our experience about 9 patients with incontinence post radical prostatectomy (out of 74 patients operated on at our Institution). We obtained an improvement or a complete cure in 78% of the treated patients. We believed that pelvic floor physiotherapy can be considered a good and safe method of treatment of incontinence after radical prostatectomy, at least in less serious cases.

Structural and immunological similarities between high molecular weight zinc ion-dependent p-nitrophenylphosphatase and fructose-1,6-bisphosphate aldolase from bovine liver

High molecular weight zinc ion-dependent acid p-nitrophenylphosphatase (HMW-ZnAPase) was purified from bovine liver to homogeneity as judged by native and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The partial sequence of the purified enzyme electroblotted on PVDF membrane reveals a 95% sequence homology with human and bovine liver fructose-1,6-bisphosphate aldolase isozyme B (FALD B). FALD B was isolated from bovine liver using an affinity elution from phosphocellulose column. FALD B from bovine liver shows a native and subunit molecular weight that is indistinguishable from that of HMW-ZnAPase. In addition, an affinity purified antiserum raised in rabbits against purified HMW-ZnAPase cross-reacts with bovine liver FALD B and rabbit muscle isozymes. Despite these similarities, HMW-ZnAPase does not show FALD activity and bovine liver FALD does not display any zinc ion-p-nitrophenylphosphatase activity. These results suggested the existence of structural and immunological similarities between bovine liver HMW-ZnAPase and FALD B. Differences in some amino acid residues in enzyme activity indicate that they may be involved in different biochemical functions.

The chromosome complement of Olea europaea L.: characterization by differential staining of the chromatin and in-situ hybridization of highly repeated DNA sequences

The chromosome complement of olive (Olea europaea L.) has been characterized by differential staining of the chromatin and chromosomal localization of highly repeated DNA sequences and ribosomal cistrons. DAPI staining produces different-sized positive bands in various locations on all the chromosomes. By combining this band pattern with the results obtained from cytological hybridization of OeTaq80, OeTaq178, and OeGEM86 DNA tandem repeats, most of the pairs can be distinguished from each other, in spite of the large number of chromosomes (2n = 46), their small size and similar morphology. Different tandem-repeated DNA sequences may be contained into single heterochromatic chromosome regions, even though there are regions where repeats of only one family are present. OeTaq80- and OeGEM86-related DNA sequences are rather specific to the heterochromatin at the chromosome ends, while most sequences related to the longer OeTaq178 probe are confined to interstitial heterochromatin. Some exceptions suggest that major chromosomal rearrangements occurred during genome evolution. Polymorphism, which may differentiate olive cultivars, was observed within chromosome pairs I, V, and VII.

Stroke after zoster ophthalmicus in a 12-year-old girl with protein C deficiency

A 12-year-old girl who had zoster ophthalmicus 10 months earlier presented with hemiparesis and corresponding basal ganglionic infarction related to middle cerebral artery branch thrombosis ipsilateral to the zoster. Hematologic evaluation disclosed protein C deficiency. This represents the first zoster-associated stroke reported in childhood associated with protein C deficiency, with extension of the latency period between zoster and infarction, previously reported to be 6 months.

Human liver high molecular weight zinc-dependent acid p-nitrophenylphosphatase. Purification and properties

Human liver contains high molecular weight-type Zn2+-dependent acid p-nitrophenylphosphatase (HMW-ZnAP). The enzyme was purified 1000-fold by a new procedure, including preparative isoelectrofocusing. The HMW-ZnAP was homogeneous in non-denaturing disk-gel electrophoresis with an MW of about 93 kDa determined by Sephadex G-100 chromatography. A single polypeptide chain of 43 kDa was detected on sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), suggesting a homodimeric structure. The isoelectric point (pI) was 7.2-7.4. Human liver HMW-ZnAP requires Zn2+-ions for activity; other divalent cations are ineffective or act as inhibitors. It dephosphorylated p-nitrophenylphosphate (pNPP) (Km = 0.24 mM), o-carboxyl phenylphosphate (oCPP) (Km = 0.92 mM) and phenylphosphate (PhP) (Km = 1.42 mM). Other substrates including [32P]-labelled casein or phosvitin, adenyl nucleotides and myo-inositol-1-phosphate, were not dephosphorylated. Human liver HMW-ZnAP obeys Michaelis-Menten kinetics with pNPP as substrate; the enzyme was competitively inhibited by inorganic phosphate (Ki = 0.55 mM), and by oCPP (Ki = 0.65 mM) and PhP (K = 1.16 mM). Adenosine monophosphate (AMP), adenosine diphosphate (ADP) and ATP displayed mixed-type inhibition. The enzyme was also inhibited by some modifiers such as EDTA, oxalate, p-chloromercurybenzoate, tartrate, imidazole, cyanide, cysteine, histidine and diethylpyrocarbonate, but not by fluoride or okadaic acid. Human liver HMW-ZnAP is sensitive to temperatures higher than 40 degrees C. The pH-dependence of the steady-state kinetic parameters indicates the existence of an essential ionizable group with a pKa of 7.25-7.50, similar to that of histidine. However, diethylpyrocarbonate inactivation experiments suggest that other amino acid residues may also be involved in enzyme catalysis.

Stable expression and purification of a secreted human recombinant prethrombin-2 and its activation to thrombin

A human prothrombin cDNA has been engineered to obtain a cDNA coding for a secreted form of human prethrombin-2. The secreted prethrombin-2 has been produced in a mammalian expression system using DXB11 cells, a mutant strain of CHO cells in which the dihydrofolate reductase gene has been deleted, and an expression vector carrying the dihydrofolate reductase cDNA. Methotrexate-induced gene amplification favored an efficient production of the recombinant protein which accumulated in the culture medium of the DXB11 cells. Growth in suspension of the stable transformants in an airlift fermenter resulted in the production of 25 mg/L recombinant prethrombin-2. The recombinant protein was purified using single-step affinity chromatography on a recombinant-hirudin column and activated by agarose gel-immobilized ecarin. All purified recombinant prethrombin-2 was activated and the generated recombinant thrombin showed catalytic properties identical to those of plasma-derived alpha-thrombin. This expression system can be used to prepare mutants of prethrombin-2 for structure-function studies investigating thrombin interactions with substrate proteins, inhibitors, and cell membranes.

Molecular cloning of a cDNA encoding an antigen which is salt-stably attached to centrosomes

A monoclonal antibody (MAB 2A8) was used for expression-cloning of a complete cDNA (1133/5) to a mRNA (3 kb) encoding a murine 76 kDa polypeptide. The N-terminal section of the polypeptide is composed of domains capable to form alpha-helical coiled-coils. Its C-terminus is proline-rich and has characteristics of the Src homology region 3 (SH3). Affinity-purified antibodies to a recombinant section of the protein show that the antigen is salt-stably associated with the centrosome throughout the cell cycle.

Synthetic octapeptide pyroGlu-Asp-Asp-Ser-Asp-Glu-Glu-Asn promotes differentiation in promyelocytic HL-60 cell line

The activity of the octapeptide pyroGlu-Asp-Asp-Ser-Asp-Glu-Glu-Asn in the control of cell growth and differentiation of human myeloblastic leukemia cells HL-60 is reported. Treatment with peptide slightly slows down the rate of cellular proliferation and this effect becomes more evident in cells grown for several weeks in the presence of the effector. An enhanced effect (40-50% inhibition respect to the control) is found in reversibly permeabilized cells and after 1% DMSO is added to the medium. Moreover the presence of peptide markedly increases the percentage of cells differentiated by DMSO and RA. The effect in DMSO-induced cells is more evident than that observed in RA-induced cells. This in agreement with our hypothesis that DMSO facilitates the peptide entry and its effect is due to an intracellular action.

High salt- and SDS-stable DNA binding protein complexes with ATPase and protein kinase activity retained in chromatin-depleted nuclei

Cell lysis in presence of SDS and proteinase K followed by salting-out of residual polypeptides by dehydration and precipitation with saturated sodium chloride solution [Miller, S.A., Dykes, D.D. and Polesky, H.F., Nucleic Acids Res., 16, 1215, 1988] efficiently resolves deproteinized DNA. However, this DNA is still associated with prominent polypeptides which remain stably attached to DNA during further treatments, e.g. during repeated salting-out steps, prolonged incubation of DNA in 1% SDS or 4 M urea at 56 degrees C and ethanol precipitation. The persistent polypeptides (62, 52 and 40 kDa) released from Ehrlich ascites cell DNA were further characterized. Microsequencing indicates that the DNA binding polypeptides are not yet characterized at the sequence level. Nuclease digestion of the DNA releases stable DNA-protein complexes with the shape of globular particles (12.8 +/- 0.8 nm) and their larger aggregates in which DNA remains protected from nuclease digestion. The isolated DNA-polypeptide complexes show ATPase (Km = 7.4 x 10(-4) M) and protein kinase activity. Antibodies reveal a parallel distribution of the complexes with chromatin, however, the complexes are retained in chromatin-depleted nuclei.

Purification and some properties of a Mg(2+)-activated acid phosphatase from rat testis

1. The acid phosphatase (AcPase, EC 3.1.3.2) IV from rat testicular tissue was purified to apparent homogeneity. 2. The enzyme displays a native molecular weight of 70 kDa determined on gel permeation chromatography on a Sephadex G-100 column and 68 kDa using linear 5-20% sucrose density gradient centrifugation. The subunit molecular weight on SDS-PAGE analysis is 67 kDa, suggesting that the enzyme is a monomeric protein. 3. The enzyme does not bind to Concanavaline A-Sepharose 4B column, indicating that it is not a glycoprotein. 4. The rat testis AcPase IV is a metal activated enzyme in which Mg2+ is the metal activating agent with a Ka = 0.88 x 10(-3) M. The Michaelis constant for p-nitrophenylphosphate, in the presence of saturating concentrations of Mg2+ ions, is 0.23 x 10(-3) M. 5. The enzyme preferentially hydrolyzes p-nitrophenylphosphate, phenylphosphate and ATP.

Molecular models of small phosphorylated chromatin peptides. Structure-function relationship and regulatory activity on in vitro transcription and on cell growth and differentiation

We previously reported the isolation of low molecular weight phosphorylated peptides from the chromatin of several tissues. The chromatin peptides show a regulatory activity on DNA in vitro transcription and on cell growth and differentiation. In this paper, we report a molecular model of the native peptides designed according to the structural information obtained by means of biochemical and mass spectrometry analysis: pyroGlu-Ala-Gly-Glu-Asp-Ser(P)-Asp-Glu-Glu-Asn. This or very similar sequences are present in many transcription factors; on the basis of the structural model we presented and of related protein sequences, we have synthesized the peptide pyroGlu-Asp-Asp-Ser-Asp-Glu-Glu-Asn. This peptide affects transcription rate in reconstituted systems in vitro and in isolated nuclei; moreover, it inhibits the growth of HL60 cells with a parallel stimulus of differentiation.

Synthetic octapeptide pyroGLU-ASP-ASP-SER-ASP-GLU-GLU-ASN controls DNA transcription in vitro by RNA polymerase II

The effect of the synthetic octapeptide pyroGLU-ASP-ASP-SER-ASP-GLU-GLU-ASN (phosphorylated by casein kinase II, CKII) on DNA transcription by RNA polymerase II has been studied. The peptide contains the acidic carboxy-terminus heptapeptide of the largest subunit of RNA polymerase II, which has been demonstrated to be a phosphorylation site for CKII. The aim of this work is to obtain some insights about the possible role of this domain in RNA polymerase II activity and DNA binding. Results demonstrated that the phosphorylated octapeptide causes strong inhibition of transcription of calf thymus DNA or pSVL SV40 plasmid DNA by RNA polymerase II, when used at concentrations between 0.4-4 micrograms/ml.

Phosphorylation of synthetic acidic peptides by casein kinase II: evidence for competition with phosphorylation of proteins involved in transcription

Phosphorylation of several synthetic acidic peptides by biochemically isolated casein kinase II (CKII) and by cellular and nuclear extracts containing CKII-like activity has been investigated. Especially the synthetic peptide pyroGlu-Asp-Asp-Ser-Asp-Glu-Glu-Asn comprising the carboxy-terminal acidic hepta-peptide of the largest subunit of RNA polymerase II was found to serve as an excellent substrate for purified CKII. Moreover, this peptide reduces the rate of 'in vitro' ATP-dependent stimulation of DNA transcription induced by the proteins in the extracts. Since the peptide itself is also significantly phosphorylated in such assays, it is supposed that it serves as a competitive substrate for the phosphorylation of proteins in the extracts whose phosphorylation seems to be a prerequisite for their activity in the transcription process. This points to the involvement of CKII and substrate(s) of CKII in the process of transcription.

Human L7a ribosomal protein: sequence, structural organization, and expression of a functional gene

A cDNA coding for the human L7a ribosomal protein (r-protein) was used to isolate the corresponding gene by screening two human genomic libraries constructed in bacteriophage lambda and in a cosmid vector. One of the cosmid clones isolated, cos1.1, contains the whole L7 alpha gene, composed of eight exons and seven introns spanning 3226 bp. As in other mammalian housekeeping genes, the promoter and the first exon of the L7 alpha reside within a CpG-rich island. Furthermore, similar to the other higher eukaryote r-protein-encoding genes characterized so far, the human L7 alpha gene has a C as the major transcriptional start point localized in a pyrimidine-rich region and lacks a canonical TATA sequence. We show that 130 bp of the human L7 alpha gene 5'-flanking region represent the minimal element required to promote its transcription. This element is strikingly conserved between the mouse and human L7 alpha genes. Finally, a comparison of the human L7 alpha gene coding sequence and the predicted amino acid (aa) sequence with the sequences of mouse L7a, rat L7a, and the homologous yeast L4 shows that the aa sequence has been highly conserved during evolution.

Protein kinase NII from calf thymus chromatin. Isolation, characterization and some functional properties

1. A protein kinase type II was purified from calf thymus chromatin using ammonium sulphate fractionation, ion exchange chromatography on DEAE and phosphocellulose and affinity chromatography on phosvitin- and casein-sepharose columns. 2. The enzyme moves as a single band in non-denaturing gel electrophoresis at pH 8.3, which coincides with the enzyme activity assayed on gel slices. 3. Sodium dodecyl sulphate gel electrophoresis shows three separate polypeptide chains having M(r) of 40,000, 38,000 and 25,000, respectively. The native M(r) was about 130,000, as measured by HPLC on Superose 12 column, suggesting a subunit structure of alpha, alpha', beta 2 type. The enzyme incubated with [gamma 32P]ATP or [gamma 32P]GTP as phosphoryl donors undergoes autophosphorylation in the M(r) = 25,000 subunit. 4. The enzyme phosphorylates casein (Km = 7 microM) and phosvitin (Km = 5 microM) but not histones and was strongly deactivated by Zn2+ ions (I50 = 0.05 mM) and heparin (I50 = 0.1 micrograms/ml). 5. The enzyme seems to be the major phosphorylating system present in the 0.35 M NaCl chromatin extract of calf thymus. The RNA polymerase II from calf thymus and RNA polymerase from E. coli are both phosphorylated by protein kinase NII. The effect of phosphorylation, which causes a remarkable increase of DNA transcription rate, was studied in vitro and extensively discussed.

Acid phosphatases in mammalian tissues. Evidence for the existence of a 57 kDa Zn(2+)-dependent acid phosphatase form

1. A comparative study of multiple forms of acid phosphatase (AcPase) in various organs of mammals was carried out. 2. These studies indicated that the high-molecular weight AcPase is preferentially expressed by tissues which undergo cell proliferation such as epithelial tissues; on the contrary, the low-molecular weight enzyme seems to be characteristic of highly differentiated tissues such as nervous, muscle and blood erythrocytes. 3. The existence of a new AcPase activated by Zn2+ ions was observed in all tissues studied with the exception of erythrocytes. 4. The enzyme shows a molecular weight of 57 kDa, is insensitive to NaF, hydrolyzes p-nitro-phenylphosphate and o-c-phenylphosphate; ATP, a-naphthyl-phosphate and beta-glycerolphosphate are also dephosphorylated.

Isolation and partial characterization of a protein kinase NII from wheat germ chromatin

A protein kinase, type NII, has been purified from wheat germ chromatin. The enzyme, which uses both ATP and GTP as phosphoryl donors, catalyzes the phosphorylation of casein, phosvitin and E. coli RNA polymerase, but not of histone proteins. Polypeptide bands at 46 kDa, 37 kDa and 25 kDa were estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Autophosphorylation of the 25 kDa subunit was observed following incubation of the purified kinase with (gamma-32P)ATP and (gamma-32P)GTP.

Acid phosphatases in the frog (Rana esculenta) skeletal muscle. Purification and some properties of the low molecular weight enzyme

1. The presence of high-Mr and low-Mr acid phosphatases [orthophosphoric-monoester phosphohydrolase, (acid optimum), EC 3.1.3.2] in the skeletal muscle of frog Rana esculenta was reported. 2. The subcellular localization and some characteristics of both enzymes were also described. 3. The low-Mr AcPase was purified to homogeneity. The enzyme did not absorb on Concanavalin A-Sepharose 4B indicating that this was not a glycoprotein. 4. The enzyme is homogeneous on polyacrylamide gel electrophoresis and moves as a single band of Mr 13.7 +/- 0.8 kDa in the presence of sodium dodecyl sulphate. 5. The Mr of the native enzyme was 14.0 +/- 1.1 kDa as determined by gel filtration on a Sephadex G-100 column. The isoelectric point was 6.02. 6. The enzyme was strongly inhibited by 1 mM Ag+, Hg2+, Sn2+ and Cu2+ while other cations both at 10(-2) and 10(-3) M showed little or no effect. 7. The enzyme was insensitive to NaF and tartrate but was strongly deactivated by formaldehyde, PMB, Iodoacetamide and Triton X-100. Phosphate was a competitive inhibitor (k1 = 0.83 mM). 8. The best substrate for the enzyme was p-nitrophenylphosphate but phenylphosphate, flavin mononucleotide and o-P-tyrosine were also hydrolyzed, though at different rates. 9. The enzyme activity was enhanced in the presence of methanol, ethanol, acetone and glycerol indicating a phosphotransferase activity.

Purification and subcellular localization of Zn-dependent acid p-nitrophenylphosphatase in frog liver and comparison with other vertebrates

Zn2(+)-dependent acid p-nitrophenylphosphatase (Zn-AcPase) from liver of Rana esculenta was purified to homogeneity. The purified enzyme moves as a single electrophoretic band at pH 8.3 in 7.5% acrylamide and was coincident with the enzyme activity. The enzyme has a molecular weight of 102,000 +/- 5,000D and is a dimer with two apparently similar polypeptide chains of 48,000 +/- 3,000D as determined by sodium dodecylsulfate gel electrophoresis. Zn-AcPase from frog liver requires Zn2+ ions for catalytic activity; other bivalent cations have little or no effect. The enzyme with a pI of 7.07 does not appear to be a glycoprotein and was associated with the soluble fraction after liver cell fractionation. The biochemical and molecular properties of frog liver Zn-AcPase were compared with that of the enzyme partially purified from carp (Cyprinus carpio), pike (Esox lucius), and rat (Rattus norvegicus).

Acid phosphatases from liver of Rana esculenta. Subcellular localization and partial characterization of multiple forms

1. Four acid phosphatases (AcPase I, II, III and IV) were found in the liver of the frog Rana esculenta. 2. AcPases I, II, III, and IV were associated with the microsomal, mitochondrial-lysosomal, nuclear and soluble fractions respectively and showed apparent molecular weights of about 240,000, 110,000, 38,000 and 17,000. 3. All the enzymes show acid pH optima, and similar Km values for p-nitrophenylphosphate. 4. AcPases I, II, and III hydrolyze most of the common phosphate esters whereas AcPase IV hydrolyzes effectively only p-nitrophenylphosphate, phenylphosphate and flavine mononucleotide. 5. AcPases I and II are inhibited by NaF and tartrate. AcPases III and IV are tartrate resistant. 6. Temperature inhibits AcPases I, II, IV, whereas it activates AcPase III.