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Functional analysis of isolated cpn10 domains and conserved amino acid residues in spinach chloroplast co-chaperonin by site-directed mutagenesis.

The possibilities of independent function of the two chaperonin 10 (cpn10) domains of the cpn10 homologue from spinach chloroplasts and the role of five conserved amino acid residues in the N-terminal cpn10 unit were investigated. Recombinant single domain proteins and complete chloroplast cpn10 proteins carrying amino acid exchanges of conserved residues in their N-terminal cpn10 domain were expressed in Escherichia coli and partially purified. The function of the recombinant proteins was tested using GroEL as chaperonin 60 (cpn60) partner for in vitro refolding of denatured ribulose-1,5-bisphosphate carboxylase (Rubisco). Interaction with cpn60 was also monitored by the ability to inhibit GroEL ATPase activity. In vitro both isolated cpn10 domains were found to be incapable of co-chaperonin function. All mutants were also severely impaired in cpn10 function. The results are interpreted in terms of an essential role of the exchanged amino acid residues for the interaction between co-chaperonin and cpn60 partner and in terms of a functional coupling of both cpn10 domains. To test the function of mutant chloroplast cpn10 proteins in vivo the cpn10 deficiency of E. coli strain CG712 resulting in an inability to assemble lambda-phage was exploited in a complementation assay. Transformation with plasmids directing the expression of mutant chloroplas cpn10 proteins in two cases restored lambda-phage assembly in this bacterial strain to the same extent as did transformation with a plasmid encoding wild-type cpn10 protein. In contrast a plasmid encoded third mutant and truncated forms of chloroplast cpn10 showed significantly reduced complementation efficiencies.

Adenosine Triphosphatases↗

Comparative sequence analysis of a single-gene conserved segment in mouse and human.

Comparative mapping and sequencing of the mouse and human genomes have defined large, conserved chromosomal segments in which gene content and order are highly conserved. These regions span megabase-sized intervals and together comprise the vast majority of both genomes. However, the evolutionary relationships among the small remaining portions of these genomes are not as well characterized. Here we describe the sequencing and annotation of a 341-kb region of mouse Chr 2 containing nine genes, including biliverdin reductase A (Blvra), and its comparison with the orthologous regions of the human and rat genomes. These analyses reveal that the known conserved synteny between mouse Chromosome (Chr) 2 and human Chr 7 reflects an interval containing one gene (Blvra/BLVRA) that is, at most, just 34 kb in the mouse genome. In the mouse, this segment is flanked proximally by genes orthologous to human chromosome 15q21 and distally by genes orthologous to human Chr 2q11. The observed differences between the human and mouse genomes likely resulted from one or more rearrangements in the rodent lineage. In addition to the resulting changes in gene order and location, these rearrangements also appear to have included genomic deletions that led to the loss of at least one gene in the rodent lineage. Finally, we also have identified a recent mouse-specific segmental duplication. These finding illustrate that small genomic regions outside the large mouse-human conserved segments can contain a single gene as well as sequences that are apparently unique to one genome.

Animals↗

Application of decision analysis to management of cerebral arteriovenous malformation.

Consideration of cerebral arteriovenous malformation (AVM) illustrates how decision analysis may be used to evaluate systematically two treatment options--surgery before bleeding occurs or conservative management. The analysis balances risk of immediate surgical mortality and morbidity against the delayed risks inherent in conservative management. Because the condition is rare and local experience therefore scant, probability estimates have to be obtained from the literature. From these probability estimates and from estimates of attractiveness of various outcomes (made in this study by a clinician) a quantitative assessment of the risks and benefits of surgical versus medical management can be calculated. The finding is that conservative treatment is preferable to surgery in patients who present with an AVM before bleeding occurs, even when the probability estimates used are those obtained under conditions more favourable to surgery. The decision also remains unchanged when different attractiveness values are assigned to possible outcomes.

Adult↗

The avian IGF type 1 receptor: cDNA analysis and in situ hybridization reveal conserved sequence elements and expression patterns relevant for the development of the nervous system.

Insulin-like growth factor type 1 receptor (IGF-1R) is a tyrosine kinase with a key role in development. The primary structure of IGF-1R is known for mammalian species, but not for birds. The avian embryo, however, provides an ideal system for the experimental study of neurogenesis. We therefore cloned the complete coding sequence of the chicken IGF-1R from a cDNA library and analyzed its embryonic expression by Northern blot and in situ hybridization. The deduced chicken IGF-1R precursor of 1363 amino acids was 85% identical to human IGF-1R and did not show deletions or insertions in critical positions, when compared to its mammalian homologues. Notably, all cysteine residues in the extracellular domains, and 15 of the 17 N-linked glycosylation sites found in human IGF-1R were also present in the chicken receptor. An 11 kb transcript was abundant in developing nervous tissues, kidney, pancreas and the gastrointestinal tract. The early in situ expression patterns in 20-somite embryos revealed high levels of IGF-1R mRNA in the neuroepithelia, notochord and somites. At embryonic day 4 (E4), high concentrations of IGF-1R transcripts were found again primarily in the neuroepithelia and, to a lesser degree, in the sensory ganglia and diverse mesenchymal derivatives. During the second half of embryonic development, IGF-1R expression in the CNS was particularly abundant in telencephalic regions, including the olfactory bulb, hippocampus, striatum and piriform cortex, and also in the optic tectum and cerebellum. By the use of cDNA cloning and in situ hybridization this study reveals conserved amino acid sequence elements between birds and mammals, and developmental expression patterns that are compatible with an important role of this receptor in growth, differentiation and maturation of the avian CNS.

Animals↗

Genetic diversity and function in the human cytosolic sulfotransferases.

Amino-acid substitutions, which result from common nonsynonymous (NS) polymorphisms, may dramatically alter the function of the encoded protein. Gaining insight into how these substitutions alter function is a step toward acquiring predictability. In this study, we incorporated gene resequencing, functional genomics, amino-acid characterization and crystal structure analysis for the cytosolic sulfotransferases (SULTs) to attempt to gain predictability regarding the function of variant allozymes. Previously, four SULT genes were resequenced in 118 DNA samples. With additional resequencing of the remaining eight SULT family members in the same DNA samples, a total of 217 polymorphisms were revealed. Of 64 polymorphisms identified within 8785 bp of coding regions from SULT genes examined, 25 were synonymous and 39 were NS. Overall, the proportion of synonymous changes was greater than expected from a random distribution of mutations, suggesting the presence of a selective pressure against amino-acid substitutions. Functional data for common variants of five SULT genes have been previously published. These data, together with the SULT1A1 variant allozyme data presented in this paper, showed that the major mechanism by which amino acid changes altered function in a transient expression system was through decreases in immunoreactive protein rather than changes in enzyme kinetics. Additional insight with regard to mechanisms by which NS single nucleotide polymorphisms alter function was sought by analysis of evolutionary conservation, physicochemical properties of the amino-acid substitutions and crystal structure analysis. Neither individual amino-acid characteristics nor structural models were able to accurately and reliably predict the function of variant allozymes. These results suggest that common amino-acid substitutions may not dramatically alter the protein structure, but affect interactions with the cellular environment that are currently not well understood.

Amino Acid Substitution↗

Risk factor analysis for breast cellulitis complicating breast conservation therapy.

Women who undergo breast conservation therapy for early-stage breast cancer can develop breast cellulitis, a complication for which risk factors are undefined. A matched case-control investigation was conducted to identify risk factors for the development of breast cellulitis among patients who have undergone breast conservation therapy. Patients comprised 17 patients with cases of breast cellulitis diagnosed after partial mastectomies that had been performed from 1992 through 1997 and 34 control patients who were matched to case-patients by date of breast lumpectomy and by primary surgeon. Statistical analyses indicated the following factors were associated with breast cellulitis: drainage of a hematoma (P=.010); postoperative ecchymosis (P=.021); lymphedema (odds ratio [OR], 10. 154; 95% confidence interval [CI], 1.348-208.860); resected breast tissue volume (OR, 1.456; 95% CI, 1.035-2.168); and previous number of breast seroma aspirations (OR, 3.445; 95% CI, 1.036-19.771). This is the first matched case-control study to identify risk factors for the development of breast cellulitis after breast conservation therapy.

Adult↗

Cost-benefit analysis: the mystique versus the reality.

Cost-benefit analysis is promoted as a method for making social policy decisions more rational. A review of its goals, procedures, assumptions, and recent applications exposes technological shortcomings and implicit value preferences. If the method is to be useful, it must be balanced by the judgment of decision makers. Consequently, the power of cost-benefit analysis to improve policy decisions depends on the political context. In a conservative environment this analysis provides a rationalization for disinvesting in social welfare. At such times social reformers would be wise to engage in political action and to challenge cost-benefit analysis.

Cost-Benefit Analysis↗

Conserved linkage between the puffer fish (Fugu rubripes) and human genes for platelet-derived growth factor receptor and macrophage colony-stimulating factor receptor.

We have cloned and sequenced the teleost homologs of the human genes encoding platelet-derived growth factor receptor-beta (PDGFR beta) and macrophage colony-stimulating factor 1 receptor (CSFIR) from the puffer fish Fugu rubripes. The Fugu PDGFR beta and CSFIR genes each consist of 21 coding exons similar to the human CSFI gene, but are considerably smaller than their human counterparts because of the smaller introns. Furthermore, the two Fugu genes are linked tandemly in a head-to-tail array similar to their human homologs with 2.2 kb of intergenic sequence. Amino acid sequences of the Fugu and human PDGFR beta and CSFIR genes show an overall homology of 45% and 39%, respectively, with the kinase domains showing a much higher degree of conservation. Dot-matrix analysis revealed several short stretches of conserved sequences in the 3' untranslated regions of the PDGFR beta genes and the adjacent promoter regions of the CSFIR genes. These conserved sequences may have a role in the regulation of expression of either or both of these closely linked genes.

Amino Acid Sequence↗

Characterization of tocopherol cyclases from higher plants and cyanobacteria. Evolutionary implications for tocopherol synthesis and function.

Tocopherols are lipophilic antioxidants synthesized exclusively by photosynthetic organisms and collectively constitute vitamin E, an essential nutrient for both humans and animals. Tocopherol cyclase (TC) catalyzes the conversion of various phytyl quinol pathway intermediates to their corresponding tocopherols through the formation of the chromanol ring. Herein, the molecular and biochemical characterization of TCs from Arabidopsis (VTE1 [VITAMIN E 1]), Zea mays (SXD1 [Sucrose Export Deficient 1]) and Synechocystis sp. PCC6803 (slr1737) are described. Mutations in the VTE1, SXD1, or slr1737 genes resulted in both tocopherol deficiency and the accumulation of 2,3-dimethyl-6-phytyl-1,4-benzoquinone (DMPBQ), a TC substrate. Recombinant SXD1 and VTE1 proteins are able to convert DMPBQ to gamma-tocopherol in vitro. In addition, expression of maize SXD1 in a Synechocystis sp. PCC6803 slr1737 knockout mutant restored tocopherol synthesis, indicating that TC activity is evolutionarily conserved between plants and cyanobacteria. Sequence analysis identified a highly conserved 30-amino acid C-terminal domain in plant TCs that is absent from cyanobacterial orthologs. vte1-2 causes a truncation within this C-terminal domain, and the resulting mutant phenotype suggests that this domain is necessary for TC activity in plants. The defective export of Suc in sxd1 suggests that in addition to presumed antioxidant activities, tocopherols or tocopherol breakdown products also function as signal transduction molecules, or, alternatively, the DMPBQ that accumulates in sxd1 disrupts signaling required for efficient Suc export in maize.

Amino Acid Sequence↗

The structural conservation of S100 protein during evolution: analysis by reactivity with a monoclonal antibody.

A hybridoma cell line producing a monoclonal antibody (A4) against bovine S100 protein has been produced by fusing mouse myeloma P3X63/Ag8 cells with spleen cells from a BALB/c mouse immunized with bovine S100 protein. A4 is of the IgG2b subclass and was purified by affinity chromatography on a protein A-Sepharose column. Brain extracts from several mammalian and one avian species reacted both with polyclonal rabbit anti-S100 protein antiserum and with A4 in a radioimmunoassay. Brain extract from dog was a notable exception. It reacted with the rabbit antiserum but not with A4. Therefore A4 reacts with a common epitope that is present on S100 proteins from different vertebrate species but is absent on dog S100 protein.

Animals↗

Functional analysis of mosquito-borne flavivirus conserved sequence elements within 3' untranslated region of West Nile virus by use of a reporting replicon that differentiates between viral translation and RNA replication.

We have developed a reporting replicon of West Nile virus (WNV) that could be used to quantitatively distinguish viral translation and RNA replication. A Renilla luciferase (Rluc) gene was fused in-frame with the open reading frame of a subgenomic replicon in the position where the viral structural region was deleted, resulting in RlucRep. Transfection of BHK cells with RlucRep RNA yielded two distinctive Rluc signal peaks, one between 2 and 10 h and the other after 26 h posttransfection. By contrast, only the 2- to 10-h Rluc signal peak was observed in cells transfected with a mutant replicon containing an inactivated viral polymerase NS5 (RlucRep-NS5mt). Immunofluorescence and real-time reverse transcriptase PCR assays showed that the levels of viral protein expression and RNA replication increased in cells transfected with the RlucRep but not in those transfected with the RlucRep-NS5mt. These results suggest that the Rluc signal that occurred at 2 to 10 h posttransfection reflects viral translation of the input replicon, while the Rluc activity after 26 h posttransfection represents RNA replication. Using this system, we showed that mutations of conserved sequence (CS) elements within the 3' untranslated region of the mosquito-borne flaviviruses did not significantly affect WNV translation but severely diminished or completely abolished RNA replication. Mutations of CS1 that blocked the potential base pairing with a conserved sequence in the 5' region of the capsid gene (5'CS) abolished RNA replication. Restoration of the 5'CS-CS1 interaction rescued viral replication. Replicons containing individual deletions of CS2, repeated CS2 (RCS2), CS3, or RCS3 were viable, but their RNA replication was dramatically compromised. These results demonstrate that genome cyclization through the 5'CS-CS1 interaction is essential for WNV RNA replication, whereas CS2, RCS2, CS3, and RCS3 facilitate, but are dispensable for, WNV replication.

3' Untranslated Regions↗

Analysis of local recurrence after breast conservative treatment for invasive breast cancer: a single institution cohort.

In a group of 900 patients treated for carcinoma of the breast, we evaluated patient-, tumour- and treatment-related parameters, predicting the success or failure of conservative treatment for invasive breast cancer. Thirty-one patients developed local recurrences which were detected within 0.1-12.1 years after treatment of the primary tumour (with a median of 6.2 years), providing a risk of 2% at 5 years and 9% at 10 years. The locally recurrent tumours and their original primary tumours of 28 patients could be retrieved from the pathology laboratory archives. These 28 tumours of the recurrence group (RG) were matched with tumours without local recurrence, the non-recurrence group, for age at time of diagnosis, duration of follow-up and T- and N-stage. The tumours were studied for type and grade of invasive tumour including the in situ component and involvement of surgical margins. In addition, the expression of cell-cycle proteins, p53, Ki-67 (MIB-1) and BCL-1, as well as HER-2/ neu oncoprotein, estrogen and progesterone receptor were investigated. We found a mean age at diagnosis for the RG of 50 years, and the mean age at time of diagnosis for the whole group of 900 patients was 56 years (p=0.003). Thirty-nine percent of the RG had a positive surgical margin, which was the case for only 18% in the control group (p=0.09). The presence of the in situ component was also correlated with increased local recurrence (p=0.022). Furthermore, local recurrence was also associated with a significantly increased occurrence of distant metastases (p=0.001). We conclude that breast conservative treatment is safe with a low local recurrence rate.

Age of Onset↗

[Analysis of the present status of conservative therapy of nephropathies].

Treatment by dialyzing represents an important contribution to the therapy of nephropathic patients. On the other hand, besides high financial costs it is not possible to forger significant social and psychic consequences of this therapy. The present paper aimed at a pharmacoeconomic evaluation of the costs of conservative treatment of nephropathic patients. The secondary aim was to compare the costs of conservative treatment in patients with markedly limited renal functions, creatinine clearance (Ccr < 0.4 ml/s), with those in patients with only slightly and medium-reduced renal functions (Ccr 0.4-1 ml/s). Health documentation from three nephrological out-patient surgeries was used to evaluate the results, the criterion for the selection of patients being a nephrological diagnosis with Ccr below 1 ml/s. The group comprised 102 patients aged 21-84 years (average age being 63.99 years), including 56 females (54.9%) and 46 males (45.1%). According to the stage of renal disease, they were divided into two groups. The patients with slightly and medium-reduced renal functions (Ccr 0.4-1.0 ml/s) represented nearly three quarters, whereas the patients with markedly reduced renal functions (Ccr < 0.4 ml/s) only slightly more than one quarter. In the group under study, the pharmacotherapeutic costs represented 2,889,778.0 SK/year (28,331.16 SK/1 patient/1 day), in patients with renal insufficiency the costs being markedly higher (47,427.3 SK/1 patient/1 day in comparison with 21,456.7 SK/1 patient/1 day). Of total pharmacotherapeutic costs, 29.38% was represented by antihypertensive agents, 24.47% by preparations supplementing essential amino acids, 14.83% by hypolipidemic agents, 14.37% by preparations supplementing calcium, 6.19% by antianaemic agents, and 7.76% by other drugs. The results demonstrate that pharmacotherapy of renal diseases is costly but in comparison with elimination methods (dialysis) it is incomparably less expensive. The spectrum of employed agents is in agreement with the present-day trends in conservative treatment which decelerates the progress of nephropathies.

Adult↗

[Identification and analysis of a group of highly conserved trs-like genes in rice].

There are at least ten transcriptional trs-like genes in rice that have been confirmed by RT - PCR and sequencing, based on the annotation results of rice genome and homologous search. These ten genes correspond to six of the ten known subunits of TRAPP complex in yeast. Four pairs of them are duplicates while the other two are unique according to the known rice genomic sequences. All of the ten genes are constitutively expressed in rice tissues and share phylogenetic homology to some extent with other eukaryotic trs-like genes in their gene structures and protein sequences.

Genes, Plant↗