HSP25 in isolated perfused rat hearts: localization and response to hyperthermia

Recent investigations concentrate on the correlation between the myocardial expression of the inducible 70-kDa heat shock protein (HSP70i) by different stress conditions and its possible protective effects. Only few studies have focused on the involvement of small heat shock proteins in this process. We analyzed the location of the small heat shock protein HSP25 in isolated cardiomyocytes as well as its location and induction in isolated perfused hearts of rats. By immunofluorescence microscopy HSP25 was found to colocalize with actin in the I-band of myofibrils in cardiomyocytes of isolated perfused hearts as well as in isolated neonatal and adult cardiomyocytes. Hyperthermic perfusion of isolated hearts for 45 min resulted in modulation of different parameters of heart function and in induction of HSP25 is constitutively expressed even in normothermic perfused (44-46 degrees C) were lethal with respect to the contractile function of the hearts. Compared to control hearts perfused at 37 degrees C, significant increases during hyperthermic perfusion at 42 degrees C and 43 degrees C were obtained for heart rate, contraction velocity and relaxation velocity. In response to hyperthermia at 43 degrees C and after subsequent normothermic perfusion for 135 min at 37 degrees C, left to control values immediately after the period of heat treatment. HSP25 is constitutively expressed even in normothermic perfused hearts as shown by Western blotting. Hyperthermia increased the content of HSP25 only in the left ventricular tissue. In contrast, HSP70i was strongly induced in all analyzed parts of the myocardium (left ventricle, right ventricle, septum). Our findings suggest a differential regulation of HSP25 and HSP70i expression in response to hyperthermia in isolated perfused hearts. The constitutively expressed HSP25 seems to be located adjacent to the myofibrils which implies a specific role of this protein even under unstressed conditions for the contractile function of the myocardium.

Early pathologic and biochemical changes in Creutzfeldt-Jakob disease: study of brain biopsies

We examined brain biopsy tissue from five patients with a neurologic syndrome consistent with Creutzfeldt-Jakob disease using Western blot analysis and immunohistochemistry for the detection of protease-resistant prion protein, in addition to histopathologic examination. Our results indicate that the formation of protease-resistant prion protein is an early event in disease pathogenesis and Western blot analysis can detect protease-resistant prion protein in the absence of structural lesions using a small amount of brain biopsy tissue.

Isolation and purification of functional bovine lung mast cells (BLMCs)

Purified pulmonary mast cells were obtained from bovine lung using a combination of enzymatic digestion of tissue, density gradient centrifugation using Percoll, and centrifugal elutriation. In the initial procedure, lung tissue was enzymatically digested with collagenase, hyaluronidase, protease and elastase in three 30 min incubations at 37 degrees C. Monodispersed cell suspensions contained between 2 and 6% mast cells. Further purification of these mast cells by Percoll gradients and elutriation consistently yielded mast cells of > 90% purity. These cells were morphologically intact, viable and functional, as determined by histamine release evoked by secretagogue challenge. Incubation of BLMCs with Pasteurella haemolytica A1 culture supernate containing leucotoxin (LCT) alone, resulted in increased histamine release compared to controls. LCT also potentiated calcium ionophore (CaI)-induced histamine release from BLMCs.

The human ribosomal protein S7-encoding gene: isolation, structure and localization in 2p25

We have identified a gene encoding the human ribosomal protein (r-protein) S7. The S7 gene contains seven exons and six introns spanning about 6 kb. Organization of the gene is similar to that of Xenopus laevis S8, the only homologous intron-containing gene isolated so far. An mRNA transcribed from this gene has an open reading frame (ORF) of 582 nucleotides (nt), which encodes a protein of 194 amino acids (22.1 kDa). The transcription start point (tsp) was mapped by a primer extension assay to a C residue within a pyrimidine-rich tract. Human S7 (hS7) is identical to rat S7 (rS7) and exhibits significant similarity with the X. laevis, insect and plant homologs. We have used fluorescence in situ hybridization (FISH) to localize S7 to chromosome 2p25.

Coronary artery thromboembolism and unexpected death in childhood and adolescence

Two cases of unexpected death in childhood and adolescence associated with coronary artery thromboembolism are reported involving a 6-year-old girl with acute rheumatic fever and left ventricular vegetations, and an 18-year-old adolescent with Down syndrome and congenital heart disease. Although coronary artery thromboembolism is rarely reported in childhood or adolescence, these cases demonstrate that careful examination of the coronary arteries during pediatric autopsy may be helpful in determining factors contributing to death, even at quite young ages. This is particularly so in the presence of predisposing cardiac pathology.

Implication of mammalian ribosomal protein S3 in the processing of DNA damage

A human apurinic/apyrimidinic endonuclease activity, called AP endonuclease I, is missing from or altered specifically in cells cultured from Xeroderma pigmentosum group-D individuals (XP-D cells) (Kuhnlein, U., Lee, B., Penhoet, E. E., and Linn, S. (1978) Nucleic Acids Res. 5,951-960). We have now observed that another nuclease activity, UV endonuclease III, is similarly not detected in XP-D cells and is inseparable from the AP endonuclease I activity. This activity preferentially cleaves the phosphodiester backbone of heavily ultraviolet-irradiated DNA at unknown lesions as well as at one of the phosphodiester bonds within a cyclobutane pyrimidine dimer. The nuclease activities have been purified from mouse cells to yield a peptide of M(r) = 32,000, whose sequence indicates identity with ribosomal protein S3. The nuclease activities all cross-react with immunopurified antibody directed against authentic rat ribosomal protein S3, and, upon expression in Escherichia coli of a cloned rat cDNA for ribosomal protein S3, each of the activities was recovered and was indistinguishable from those of the mammalian UV endonuclease III. Moreover, the protein expressed in E. coli and its activities cross-react with the rat protein antibody. Ribosomal protein S3 contains a potential nuclear localization signal, and the protein isolated as a nuclease also has a glycosylation pattern consistent with a nuclear localization as determined by lectin binding. The unexpected role of a ribosomal protein in DNA damage processing and the unexplained inability to detect the nuclease activities in extracts from XP-D cells are discussed.

[Incidence and increase in type I allergies to rubber gloves in dental medicine students]

The prevalence of type I allergy against latex was investigated in dental students by questionnaire, prick tests and the determination of specific IgE antibodies. Positive prick tests against different latex fluids were found in 18 (8.7%) of 206 students, with clinical relevance in 11 cases. When the total number of students in each semester was taken into account an increase in the minimal prevalence of clinically relevant latex allergy from 2% in the second semester to 10.4% in the tenth semester was seen. A history of glove intolerance presenting as a wheal-and-flare reaction was associated with a type I allergy against latex in only 50% of the affected subjects. Atopic diseases and hand eczema of different causes proved to be risk factors in 16 and 5 of 18 students with latex allergy, respectively. A high-ammonia accelerator-free latex fluid proved to be a very reliable test medium compared to the less sensitive determination of specific IgE antibodies to latex.

Arrangement of mRNA at the decoding site of human ribosomes. 18S rRNA nucleotides and ribosomal proteins cross-linked to oligouridylate derivatives with alkylating groups at either the 3' or the 5' termini

Affinity labeling of human placental 80S ribosomes with mRNA analogs of up to 12 uridyl residues, i.e. alkylating derivatives of oligouridylates bearing either 4-(N-2-chloroethyl-N-methylamino)benzylmethylphosphamide group at the 5'-termini or 2',3'-O-[4-(N-2-chloroethyl-N-methylamino)]benzylidene residue attached to the 3'-termini, in the presence of cognate Phe-tRNA(Phe) has been investigated. All the mRNA analogs modified only the 40S subunit. The fraction of 18S rRNA modified by the mRNA analogs with the alkylating group at the 5'-end decreased dramatically with extension of the reagent oligouridylate moiety. Nucleotides of 18S rRNA alkylated with the mRNA analogs were determined using a reverse transcription technique. For the mRNA analogs with the alkylating groups at the 3'-termini, G1702 and G1763/G1764 were identified as the cross-linking sites. The intensities of the bands corresponding to reverse transcriptase stops depended on the length of the reagent oligouridylate moieties. Cross-linking sites of the mRNA analogs with the alkylating group at the 5'-termini on 18S rRNA were A1023, C1026, C1057 and A1058 for the (pU)3 and (pU)4 derivatives and a single nucleotide C1057 for the (pU)6 one. Ribosomal protein S26 was found as the main target of modification with the same derivatives of (pU)6 and (pU)12.

Induction of the small stress protein, hsp25, in Ehrlich ascites carcinoma cells by anticancer drugs

Treatment of in vitro cultured Ehrlich ascites carcinoma cells with cisplatin, daunomycin, doxorubicin, cytosine arabinoside, 3'-fluorodeoxythymidine, colchicine and vincristine in cytostatically effective concentrations results in significantly increased levels of the small stress protein, hsp25, as analyzed by immunoblotting. However, no induction of hsp25 could be detected after treatment of the tumour cells with 5-fluorouracil, aminopterin, amethopterin, mithramycin and cyclophosphamide. None of these cytostatic drugs induces hsp70.

Peptidoleukotriene (pLT) release from guinea pig lung mast cells

Guinea pig lung mast cells can be isolated and purified to high purity. This has given us the opportunity to study in greater detail mediator release from these cells. Both immunologic (ovalbumin sensitized) and nonimmunologic (calcium ionophore, CaI) stimuli caused a dose-dependent release of histamine and pLT from monodispersed lung cells and highly purified lung mast cells. Examination of the time release curve for pLT revealed a 5-min lag in the release of this mediator and a peak release at 60 min after challenge with antigen. Verification of pLT release was obtained by use of the 5-lipoxygenase inhibitor A64077 (Zileuton). Pretreatment of lung mast cells with the 5-lipoxygenase inhibitor prevented release of pLT by either antigen or CaI but had no appreciable effect on histamine release (HR). The pulmonary mast cell appears to be an important contributor to pLT release in the guinea pig lung.

[Explosive metastasis of a cancer of the kidney pelvis in analgesic kidney]

A 48-year-old male experienced sudden pain in the right flank and macrohematuria with subsequent repeated episodes of painless macrohematuria. In the radiological work-up, CT was interpreted as inflammatory enlargement of the right kidney and MRI diagnosed renal vein thrombosis. There was some suspicion that there might be a malignancy. Five months later the patient had to be admitted to the hospital, because of increasing flank pain, desiccation and general signs of inflammatory disease. Radiological changes compatible with pulmonary metastases were found. Biopsy of enlarged mediastinal lymph nodes revealed undifferentiated carcinoma. Because of the expression of Cytokeratin primary urothelial carcinoma was suspected. The patient then deteriorated rapidly. No further specific therapy could be carried out. Death was chiefly caused by respiratory insufficiency 5 months after the first episode of pain and 1 month after admission. Autopsy revealed a poorly differentiated urothelial carcinoma of the right renal pelvis, with extensive carcinomatous angiomatosis and metastases to the left kidney, lungs, and regional and mediastinal lymph nodes. Independently of the carcinoma, both kidneys also showed interstitial nephritis, papillary necrosis and capillarosclerosis, compatible with analgesic-user kidney ("phenacetin kidney") in the absence of a corresponding history.

Expression of heat shock proteins in the normal and stunned porcine myocardium

OBJECTIVE

The aim was to examine the expression of ubiquitin (Ub), 27 kDa heat shock protein (hsp27), and hsp60 mRNA in normal and briefly ischaemic and reperfused porcine myocardium:

METHODS

The left anterior descending coronary artery was occluded for two periods of 10 min separated by 30 min of reperfusion. After the second occlusion the myocardium was reperfused up to 210 min. Tissue from ischaemic, ischaemic-reperfused, and non-ischaemic regions of the heart was analysed by northern and slot blot hybridisation and nuclear run-on transcription assays employing radiolabelled cDNA probes for Ub, hsp27, and hsp60, as well as by western blot using monoclonal antibodies recognising Ub protein conjugates and antiserum recognising hsp27.

RESULTS

Systolic wall thickening was significantly decreased at 30 min reperfusion after both occlusions and remained depressed at longer periods of reperfusion. Using northern blot hybridizations, several mRNAs encoding Ub, 0.9 kb mRNA encoding hsp27, and 2.2 kb mRNA encoding hsp60 were detected in sham operated, non-ischaemic, and ischaemic myocardial tissues. Densitometric analysis of northern and slot blot hybridisation signals showed significant increase of basal tissue levels of Ub mRNA in stunned regions only during the 30 min of the second reperfusion period. Increased levels of hsp27 mRNA in stunned tissue were already noted at the first ischaemic period and were sustained compared to control during the subsequent periods of reperfusion. Changes in hsp60 mRNA tissue levels were not observed during ischaemia and subsequent reperfusions. Transcription of the Ub and hsp27 genes was increased during 30 and 120 min of the second reperfusion period. The transient enhancement of tissue levels of Ub mRNA was associated with temporary formation of new Ub-protein conjugates. However, the increased synthesis of mRNA encoding hsp27 was not followed by changes of hsp27 protein content in myocardial tissue.

CONCLUSIONS

The findings support the hypothesis that molecular damage occurs in stunned myocardium; however, the target molecules remain to be recognised.

Delineation of positive and negative control elements within the promoter region of the murine leukemia inhibitory factor (LIF) gene

Leukaemia inhibitory factor (LIF) is a multifunctional growth and differentiation factor with activities in both the adult and the embryo. The expression of LIF appears to be tightly regulated, as the levels of constitutive expression in most tissues and cell lines is extremely low. In this report we have identified three sequence elements within the 5'-flanking region of the murine LIF gene which control the constitutive action of the LIF promoter. A nested set of DNA fragments from the LIF gene 5'-flanking region was placed upstream of the chloramphenicol acetyltransferase (CAT) gene and assayed for their ability to direct chloramphenicol acetyltransferase (CAT) expression in STO-fibroblasts. The essential promoter of the LIF-gene, giving rise to low levels of CAT expression, was found to require the major start-site of transcription (+1), a TATA-box (-31) and up to 72 additional 5' nucleotides (-32 to -103). A negative regulatory element which abolished CAT-activity was identified between positions -360 and -249. The SV40 enhancer element was able to override this apparent negative element. In addition, an apparent positive control element in the LIF 5'-flanking region, between positions -860 and -661 was identified which was also able to override this negative effect.

Development and tissue-specific distribution of mouse small heat shock protein hsp25

We have investigated the developmental and tissue-specific distribution of the mouse small hsp25 by immunohistology using an antibody that specifically identifies hsp25. Our analysis shows that the relative amount of hsp25 increases during embryogenesis. Through days 13-20 of embryogenesis, hsp25 accumulation is predominant in the various muscle tissues, including the heart, the bladder, and the back muscles. hsp25 is detectable also in neurons of the spinal cord and the purkinje cells. Furthermore analysis of the closely related alpha, B-crystallin shows that in several tissues, including the bladder, the notochordal sheath and the eye lens both proteins are coexpressed. Our studies demonstrate that mammalian hsp25 accumulation is developmentally regulated during mouse embryogenesis and support the view of an important functional role of small heat shock proteins in normal cell metabolism.

Human ribosomal protein S3a: cloning of the cDNA and primary structure of the protein

The amino acid (aa) sequence of human ribosomal protein S3a (hRPS3a) was deduced partially from the nucleotide sequence of the corresponding cDNA and confirmed by direct aa sequencing from the N terminus of the purified hRPS3a protein. The cDNA clone was isolated from a cDNA expression library in the pEX vector using antibodies. The hRPS3a protein has 263 aa and its calculated M(r) is 29 813.

The small heat shock protein hsp25 is accumulated in P19 embryonal carcinoma cells and embryonic stem cells of line BLC6 during differentiation

Murine embryonal carcinoma and embryonic stem cell lines were investigated with regard to the occurrence of the small heat shock protein hsp25 during cell growth and differentiation. In the embryonal carcinoma cell line F9 considerable constitutive levels of hsp25 were observed which could be slightly increased by treatment with retinoic acid. No hsp25 was found, however, in the embryonal carcinoma cell line PCC4. When analyzing the pluripotent embryonal carcinoma cell line P19 and the pluripotent embryonic stem cell line BLC6, both characterized by high differentiation capacity, no hsp25 was observed under cell culture conditions maintaining the undifferentiated state. Induction of differentiation caused by prolonged cell culture, retinoic acid treatment, or embryoid body formation, however, resulted in an increase of the level of hsp25. The finding that hsp25 is accumulated in a differentiation-dependent manner suggests that this protein is associated with processes involved in differentiation. Therefore, hsp25 can be regarded as a marker of differentiation in the investigated embryonal carcinoma cell line P19 and the embryonic stem cell line BLC6.

Cell-free phosphorylation of the murine small heat-shock protein hsp25 by an endogenous kinase from Ehrlich ascites tumor cells

The small heat-shock protein hsp25 of the Ehrlich ascites tumor exists in one non-phosphorylated (hsp25/1) and two phosphorylated (hsp25/2, hsp25/3) isoforms. In stationary phase tumor cells, a protein kinase activity was detected which phosphorylates hsp25/1, resulting in the formation of several phosphorylated hsp25 isoforms, including those occurring naturally in the tumor. Cell-free phosphorylation of hsp25 required Mg2+ and ATP and was independent of Ca2+, phosphatidylserine, cAMP and cGMP. Polymyxin B inhibited, specifically, hsp25 phosphorylation, whereas trifluoperazine, staurosporine and the protein inhibitor of protein kinase A had no effect. In its properties, the hsp25 phosphorylating kinase differs from other common kinases such as protein kinases A and C, calcium/calmodulin-dependent kinases, and the ribosomal protein S6 kinase.

Eukaryotic initiation factors eIF-2 and eIF-3: interactions, structure and localization in ribosomal initiation complexes

More than ten different protein factors are involved in initiation of protein synthesis in eukaryotes. For binding of initiator tRNA and mRNA to the 40S ribosomal subunit, the initiation factors eIF-2 and eIF-3 are particularly important. They consist of several different subunits and form stable complexes with the 40S ribosomal subunit. The location of eIF-2 and eIF-3 in these complexes as well as the interactions of the individual components have been analyzed by biochemical methods and electron microscopy. The results obtained are summarized in this article, and a model is derived describing the spatial arrangement of eIF-2 and eIF-3 together with initiator tRNA and mRNA on the 40S subunit. Conclusions on the location of functionally important sites of eukaryotic small ribosomal subunits are discussed with regard to the respective location of these sites in the prokaryotic counterpart.

Structural organization of the genes for murine and human leukemia inhibitory factor. Evolutionary conservation of coding and non-coding regions

Leukemia inhibitory factor, LIF, is a glycoprotein with multiple activities in both the adult and the embryo. LIF appears to be encoded by a unique gene in both mouse and man, although the 3'-untranslated region of the mouse LIF gene gives a complex hybridization pattern on Southern blots. The complete nucleotide sequences of both the murine and human LIF genes and their flanking regions (8.7 and 7.6 kilobase pairs, respectively) were determined and compared. Both genes comprise three exons, two introns and an unusually long 3'-untranslated region (3.2 kilobase pairs), specificying a mRNA of approximately 4.1 kilobases. Two start sites of LIF-transcription were determined, by S1-nuclease protection and by a novel approach involving the polymerase chain reaction. S1-nuclease protection revealed a start site 60-64 base pairs upstream of the translational start codon and immediately downstream of a TATA box (TATATAAAT). The PCR approach identified a second transcriptional start site 160 base pairs 5' of the start codon and adjacent to a "TATA-like" element (CATAATTT). A comparison of the murine and human LIF gene sequences revealed a high degree of conservation in the coding regions and in segments of the untranslated and flanking regions. Seven segments displaying greater than 75% homology were identified, with the 5' and 3' ends of the transcription unit revealing the highest degree of homology. These conserved regions represents potential cis-acting control elements.

In vivo transformation of factor-dependent hemopoietic cells: role of intracisternal A-particle transposition for growth factor gene activation

Cells of the granulocyte-macrophage colony stimulating factor (GM-CSF) or multi-lineage colony stimulating factor (Multi-CSF) dependent line FDC-P1 undergo leukemic transformation after injection into irradiated DBA/2 mice. About one third of factor-independent FDC-P1 variants isolated from leukemic animals express GM-CSF or Multi-CSF, assessed either by bioassay or by sensitive RNA detection using the polymerase chain reaction. All of the GM-CSF-secreting lines studied had a rearrangement in one allele of the GM-CSF gene, three of four Multi-CSF-secreting lines had Multi-CSF gene rearrangements, while factor-independent lines lacking evidence of growth factor production had no demonstrable CSF gene alterations. All rearrangements were characterized by insertions of novel DNA in the 5'-flanking regions of the CSF genes. The inserted segments of DNA varied in size between 0.35 and 6.5 kb and displayed restriction enzyme cleavage maps reminiscent of intracisternal A-particle (IAP) genomes. This was confirmed in two cases by molecular cloning and nucleotide sequence analysis. In these instances, the insertion consisted of solitary IAP long terminal repeats. The transformation system described provides a model for the study of IAP transpositions and their effects on gene activation.

Immunoelectron microscopic studies on the location of ribosomal proteins on the surface of the 40S ribosomal subunit from rat liver

Seven ribosomal proteins have been localized by means of immunoelectron microscopy on the surface of the 40S ribosomal subunit from rat liver using monospecific antibodies. The location of ribosomal proteins S13/16, S19, and S24 is described for the first time, and that of ribosomal proteins S2, S3, S3a, and S7, which has been published previously on the basis of experiments performed with less well characterized antibody preparations [Lutsch et al., Mol. Gen. Genet. 176, 281-291 (1979) and Biomed. Biochim. Acta 42, 705-723 (1983)], is corrected in this paper. The results are discussed with respect to the involvement of these proteins in functional sites of the 40S ribosomal subunit.

Structural transition in the metal-free hexamer of protein-engineered [B13 Gln]insulin

For hexamer formation of native insulin the repulsive potential of six B13 Glu carboxylate groups coming together in the centre is overcome by zinc binding to B10 His. Substitution of Gln for Glu in position B13 by site-directed mutagenesis, i.e. replacement of the repelling carboxylates by amide groups, which are offering H-bonding potential, enhances association and allows a metal-free hexamer to form. Merely upon addition of zinc ions this hexamer undergoes the T6----T3R3 respectively T6----R6 structural transition which in the native 2Zn insulin hexamer is inducible only by additives like inorganic anions or phenolic compounds. [B13 Gln]Insulin hexamers are transformed by phenolic compounds, but not by anions, even in the absence of any metal. The structural transformation of insulin can thus be brought about in two ways: By inorganic ions with the zinc ions as their points of attack, which preexist in the nontransformed hexamer, and by phenol, for which the binding sites close to the B5 histidines come into existence only with the transformation. Therefore transformed and non-transformed hexamers, i.e. molecules with helical and extended B chain N-terminus, must be related in a dynamic equilibrium. Phenol acts as a wedge jamming the structure in the transformed state and trapping the zinc ions. Combination of transformed 2Zn[B13 Gln]insulin and metal-free native insulin in the absence of additives results in a redistribution of the zinc ions in favour of native insulin which is an outcome of the dynamic equilibrium and also demonstrates an influence of B13 charge on metal binding affinity. Transformation of a single subunit in a hexamer would lead to bad contacts.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular cloning, sequencing and expression in Escherichia coli of the 25-kDa growth-related protein of Ehrlich ascites tumor and its homology to mammalian stress proteins

The growth-related 25-kDa protein (p25) of Ehrlich ascites tumor (EAT) has been characterized by molecular cloning and sequencing of cDNA clones detected by hybridization with oligonucleotide probes synthesized according to the amino acid sequence of a tryptic peptide of p25. Detection of p25 mRNA in EAT of the exponential growth phase and of the stationary phase using cDNA-derived RNA probes demonstrated that the abundance of p25 mRNA is also growth-related. High-level expression of p25 in Escherichia coli has been established by oligonucleotide-directed mutagenesis of cDNA and insertion of the mutated cDNA into a T7-promoter expression vector. Recombinant p25 from the expressed cDNA sequence has been shown to comigrate with EAT p25 in electrophoresis and to react with antibodies against the EAT p25. On the amino acid level, p25 shows about 80% sequence homology to the human stress protein hsp27. Furthermore, p25 has similar isoforms of phosphorylation as demonstrated for small mammalian stress proteins from rat and human. From the results obtained, it is concluded that p25 is a mammalian stress protein, the abundance of which is related to growth characteristics of the Ehrlich ascites tumor.