Accumulation of creatine kinase mRNA during myogenesis: molecular cloning of a B-creatine kinase cDNA

Effect of selenium deficiency on the antioxidative status and muscle damage in growing turkeys

An experiment investigated the effect of different selenium supplementations on the antioxidant defence system and on the occurrence of muscle dystrophy in growing turkeys. Newly hatched male turkeys (B.U.T. Big 6) were divided into eight groups of 18 turkeys each and fed either a basal diet (selenium < 0.010 mg/kg diet), or the basal diet supplemented with 0.10; 0.15; 0.20; 0.25; 0.30; 0.35 or 0.40 mg selenium/kg diet in the form of sodium selenate. Vitamin E was adequately supplemented in all diets. After 35 days, muscle damage parameters including aspartate aminotransferase, creatine kinase, creatine kinase M and B were significantly increased in the selenium deficient Group I. A significant reduction of weight gain, feed consumption and selenium dependent glutathione peroxidase activity was also observed in the liver of selenium deficient birds. The ratio of oxidised glutathione (GSSG) to total glutathione (tGSH) was substantially altered in the selenium deficient Group I as well as in Group II (0.10 mg selenium/kg feed). The activity of glutathione reductase (GR) and glutathione-S-transferase (GST) was not affected by selenium deficiency.

Heterogeneous cellular expression of creatine kinase isoenzyme during normal rat heart development

The degree to which developmentally related alterations in cardiac creatine kinase (CK) activity reflect modification of CK isoenzyme gene expression remains uncertain. The present studies addressed this question by assessing multiple aspects of CK in rat heart during the perinatal to adult transition. In addition to whole tissue, isolated and purified muscle and nonmuscle cells were studied, as well as myofibrillar, mitochondrial, and cytosolic subcellular fractions. Whole homogenate CK enzyme specific activity nearly doubled during the weanling to adult developmental period. Muscle cell CK activity increased by a similar magnitude. Nonmuscle cell activity decreased. In the adult heart, both myofibrillar and mitochondrial CK activities were augmented versus the weanling heart. The cytoplasmic fraction activity held constant during development. Electrophoretic isoenzyme analyses of both weanling and adult cardiac muscle cells indicated the presence of mitochondrial CK and MM-CK isoforms. Weanling heart nonmuscle cells contained mitochondrial, MM, MB, and BB isoforms; however, BB isoform was not detected in the adult heart nonmuscle cells. Arrhenius plots provided information regarding heart muscle and nonmuscle cell alterations during development. CK activation energies were also determined for whole tissue, muscle/nonmuscle cells, myofibrils, mitochondria, and cytosol. Results demonstrate that heterogeneous muscle/nonmuscle cellular composition and differential myofibrillar/mitochondrial subcellular composition account for normal, developmentally related changes in heart CK enzyme activity. CK isoenzyme gene expression changes were not detected in cardiac muscle cells, and transition of CK-B to CK-M gene expression is limited to nonmuscle cells during normal, weanling to adult development in the rat heart.

bFGF induces BCK promoter-driven expression in muscle via increased binding of a nuclear protein

Changes in gene expression occurring during skeletal muscle differentiation are exemplified by downregulation of brain creatine kinase (BCK) and induction of muscle creatine kinase (MCK). Although both are transcriptionally regulated, there appears to be no transcription factor-element overlap, suggesting that their coordinate expression results from culture medium-related influences. Basic fibroblast growth factor (bFGF) prevents myogenesis and represses MCK expression by inhibiting transcriptional activation. It was hypothesized that bFGF similarly influenced BCK by inducing its expression. Accordingly, BCK promoter constructs were transiently transfected into C2C12 cells and, after a switch to differentiation medium, were treated with bFGF, bFGF plus herbimycin, adenosine 3',5'-cyclic monophosphate (cAMP), or phorbol 12-myristate 13-acetate (PMA). Analyses demonstrated that bFGF responsiveness was contained within a 33-base pair element. Electromobility shift assays showed that bFGF induction increased the abundance of the nuclear factor binding the element. Both effects were prevented by herbimycin. Neither cAMP nor PMA specifically induced the construct containing the bFGF-responsive element. The induced factor required phosphorylation to bind, implying that bFGF-mediated increases in binding may be due to transcription factor phosphorylation.

Evolution of the creative kinases. The chicken acidic type mitochondrial creatine kinase gene as the first nonmammalian gene

In both mammals and birds, the creatine kinase (CK) family consists of four types of genes: cytosolic brain type (B-CK); cytosolic muscle type (M-CK); mitochondrial ubiquitous, acidic type (Mia-CK); and mitochondrial sarcomeric, basic type (Mib-CK). We report here the cloning of the chicken Mia-CK cDNA and its gene. Amino acid sequences of the mature chicken Mi-CK proteins show about 90% identity to the homologous mammalian isoforms. The leader peptides, however, which are isoenzyme-specifically conserved among the mammalian Mi-CKs, are quite different in the chicken with amino acid identity values compared with the mammalian leader peptides of 38.5-51.3%. The chicken Mia-CK gene spans about 7.6 kilobases and contains 9 exons. The region around exon 1 shows a peculiar base composition, with more than 80% GC, and has the characteristics of a CpG island. The upstream sequences lack TATA or CCAAT boxes and display further properties of housekeeping genes. Several transcription factor binding sites known from mammalian Mi-CK genes are absent from the chicken gene. Although the promoter structure suggests a ubiquitous range of expression, analysis of Mia-CK transcripts in chicken tissues shows a restricted pattern and therefore does not fulfill all criteria of a housekeeping enzyme.

Mouse p53 represses the rat brain creatine kinase gene but activates the rat muscle creatine kinase gene

The creatine kinases (CK) regenerate ATP for cellular reactions with a high energy expenditure. While muscle CK (CKM) is expressed almost exclusively in adult skeletal and cardiac muscle, brain CK (CKB) expression is more widespread and is highest in brain glial cells. CKB expression is also high in human lung tumor cells, many of which contain mutations in p53 alleles. We have recently detected high levels of CKB mRNA in HeLa cells and, in this study, have tested whether this may be due to the extremely low amounts of p53 protein present in HeLa cells. Transient transfection experiments showed that wild-type mouse p53 severely repressed the rat CKB promoter in HeLa but not CV-1 monkey kidney cells, suggesting that, in HeLa but not CV-1 cells, p53 either associates with a required corepressor or undergoes a posttranslational modification necessary for CKB repression. Conversely, mouse wild-type p53 strongly activated the rat CKM promoter in CV-1 cells but not in HeLa cells, suggesting that, in CV-1 cells, p53 may associate with a required coactivator or is modified in a manner necessary for CKM activation. The DNA sequences required for p53-mediated modulations were found to be within bp -195 to +5 of the CKB promoter and within bp -168 to -97 of the CKM promoter. Moreover, a 112-bp fragment from the proximal rat CKM promoter (bp -168 to -57), which contained five degenerate p53-binding elements, was capable of conferring p53-mediated activation on a heterologous promoter in CV-1 cells. Also, this novel p53 sequence, when situated in the native 168-bp rat CKM promoter, conferred p53-mediated activation equal to or greater than that of the originally characterized far-upstream (bp -3160) mouse CKM p53 element. Therefore, CKB and CKM may be among the few cellular genes which could be targets of p53 in vivo. In addition, we analyzed a series of missense mutants with alterations in conserved region II of p53. Mutations affected p53 transrepression and transactivation activities differently, indicating that these activities in p53 are separable. The ability of p53 mutants to transactivate correlated well with their ability to inhibit transformation of rat embryonic fibroblasts by adenovirus E1a and activated Ras.

Mouse p53 represses the rat brain creatine kinase gene but activates the rat muscle creatine kinase gene

The creatine kinases (CK) regenerate ATP for cellular reactions with a high energy expenditure. While muscle CK (CKM) is expressed almost exclusively in adult skeletal and cardiac muscle, brain CK (CKB) expression is more widespread and is highest in brain glial cells. CKB expression is also high in human lung tumor cells, many of which contain mutations in p53 alleles. We have recently detected high levels of CKB mRNA in HeLa cells and, in this study, have tested whether this may be due to the extremely low amounts of p53 protein present in HeLa cells. Transient transfection experiments showed that wild-type mouse p53 severely repressed the rat CKB promoter in HeLa but not CV-1 monkey kidney cells, suggesting that, in HeLa but not CV-1 cells, p53 either associates with a required corepressor or undergoes a posttranslational modification necessary for CKB repression. Conversely, mouse wild-type p53 strongly activated the rat CKM promoter in CV-1 cells but not in HeLa cells, suggesting that, in CV-1 cells, p53 may associate with a required coactivator or is modified in a manner necessary for CKM activation. The DNA sequences required for p53-mediated modulations were found to be within bp -195 to +5 of the CKB promoter and within bp -168 to -97 of the CKM promoter. Moreover, a 112-bp fragment from the proximal rat CKM promoter (bp -168 to -57), which contained five degenerate p53-binding elements, was capable of conferring p53-mediated activation on a heterologous promoter in CV-1 cells. Also, this novel p53 sequence, when situated in the native 168-bp rat CKM promoter, conferred p53-mediated activation equal to or greater than that of the originally characterized far-upstream (bp -3160) mouse CKM p53 element. Therefore, CKB and CKM may be among the few cellular genes which could be targets of p53 in vivo. In addition, we analyzed a series of missense mutants with alterations in conserved region II of p53. Mutations affected p53 transrepression and transactivation activities differently, indicating that these activities in p53 are separable. The ability of p53 mutants to transactivate correlated well with their ability to inhibit transformation of rat embryonic fibroblasts by adenovirus E1a and activated Ras.

Sequence homology and structure predictions of the creatine kinase isoenzymes

Comparisons of the protein sequences and gene structures of the known creatine kinase isoenzymes and other guanidino kinases revealed high homology and were used to determine the evolutionary relationships of the various guanidino kinases. A 'CK framework' is defined, consisting of the most conserved sequence blocks, and 'diagnostic boxes' are identified which are characteristic for anyone creatine kinase isoenzyme (e.g. for vertebrate B-CK) and which may serve to distinguish this isoenzyme from all others (e.g. from M-CKs and Mi-CKs). Comparison of the guanidino kinases by near-UV and far-UV circular dichroism further indicates pronounced conservation of secondary structure as well as of aromatic amino acids that are involved in catalysis.

Multiple positive and negative elements regulate human brain creatine kinase gene expression

We characterized the developmental expression of the brain creatine kinase (BCK) gene in the C2C12 myogenic cell line with the use of isoenzyme, Western blot, and Northern blot analyses. The results show that both BCK subunit protein and mRNA are upregulated early in myogenesis, and then downregulated in fully differentiated myotubes. To characterize the transcriptional regulatory mechanisms, a chimeric construct containing 1.2 kilobase pairs of 5'-flanking DNA from the human BCK gene placed upstream of the chloramphenicol acetyltransferase gene in the promoterless plasmid pSVOCAT was transiently transfected into C2C12 cells. In myoblasts and differentiating myotubes, the time course of expression of the constructs paralleled that of endogenous BCK mRNA. Additional constructs prepared by deleting 5'-flanking DNA were also transfected into C2C12 cells. All constructs were preferentially expressed in myoblasts relative to myotubes with absolute levels of expression increasing with deletion of 5'-flanking DNA. In nonmyogenic cells expression of the plasmids also increased with deletion of 5'-flanking DNA. An element from -1150 to -388 was isolated and found to be capable of suppressing expression of the BCK promoter and of heterologous promoters independent of orientation and position and hence to function as a silencer. Thus, BCK expression is mediated by sequences contained in the 5'-flanking DNA, including negative elements active in both C2C12 cells and nonmyogenic cells and elements that mediate the developmental expression of the BCK gene in C2C12 myogenic cells.

Creatine kinase isozyme expression in embryonic chicken heart

The distribution pattern of creatine kinase (EC 2.7.3.2) isozymes in developing chicken heart was studied by immunohistochemistry. Creatine kinase M, which is absent from adult heart, is transiently expressed between 4 and 11 days of incubation. During that period, numerous muscular cells in the roof and septum of the atrium, in the interventricular septum and on top of the trabeculae cordis and at the rim of the outflow tract stain strongly with a polyclonal antibody that is specific for the M subunit. In the ventricle and outflow tract, the M-positive cells are found mainly subendocardially and in the right half, at the transition of conducting and working myocytes. Creatine kinase B, which is the predominant adult isozyme, is initially expressed to a high concentration in a small group of disperse myocardial cells in upstream part of the inflow tract. When compared to the expression pattern of cardiac myosin heavy chains, the observed creatine kinase expression pattern suggests that M-positive cells are mainly found in areas that participate in the formation of cardiac conductive tissue, whereas B-positive cells are first found in areas that are involved in the generation of cardiac rhythm.

Structure and expression of the human creatine kinase B gene

Various cDNAs for creatine kinase type B (CK-B) were isolated from human cDNA libraries using a 26-oligonucleotide guess-mer probe. One of the cDNAs appeared to be almost full-length and contained an open reading frame coding for the 381 amino acid residues of the human CK-B polypeptide. The nucleotide sequences of the translated region as well as the primary protein structure show a high degree of homology with known CK-B and CK-M sequences of other vertebrates. The level of CK-B RNA as a measure of CK-B gene activity was determined in various human tissues and cultured cells. Our results confirm that CK-B is expressed in a tissue-specific manner and give support to the previously proposed relation between CK-B gene activity and cell proliferation. Screening of genomic DNA with various cDNA regions as probes revealed that there is only one CK-B gene per haploid genome. Gene cloning and sequencing indicated that CK-B is coded for by a relatively small gene of 3.2 kb in size, which is partially overlapped by an HTF island (A. P. Bird (1986) Nature (London) 321, 557-558) with an extremely high G + C content at its 5' end.

Human creatine kinase: isolation and sequence analysis of cDNA clones for the B subunit, development of subunit specific probes and determination of gene copy number

cDNA clones for human B creatine kinase were isolated from human brain and placenta libraries. The entire coding and 3' untranslated regions, as well as 23 bp of the 5' untranslated region were sequenced. Complete sequence identity was found among the clones, with the exception of an area of heterogeneity among the 3' untranslated region of the brain and placenta clones. A 77.7% nucleotide sequence identity was found between the coding region of human B creatine kinase and our previously reported human M creatine kinase. In contrast, no homology was found in the 3' untranslated regions. Probes were constructed from the nonconserved 3' untranslated regions of human M and B creatine kinase and were shown to be highly specific. Southern transfers of total genomic DNA derived from human placenta and digested to completion with several restriction enzymes were probed with the MCK and BCK specific probes producing single hybridization bands. These results suggest that creatine kinase M and B are single copy genes in the human genome.