Locus determining the human sperm-specific lactate dehydrogenase, LDHC, is syntenic with LDHA

From the data presented in this report, the human LDHC gene locus is assigned to chromosome 11. Three genes determine lactate dehydrogenase (LDH) in man. LDHA and LDHB are expressed in most somatic tissues, while expression of LDHC is confined to the germinal epithelium of the testes. A human LDHC cDNA clone was used as a probe to analyze genomic DNA from rodent/human somatic cell hybrids. The pattern of bands with LDHC hybridization is easily distinguished from the pattern detected by LDHA hybridization, and the LDHC probe is specific for testis mRNA. The structural gene LDHA has been previously assigned to human chromosome 11, while LDHB maps to chromosome 12. Studies of pigeon LDH have shown tight linkage between LDHB and LDHC leading to the expectation that these genes would be syntenic in man. However, the data presented in this paper show conclusively that LDHC is syntenic with LDHA on human chromosome 11. The terminology for LDH genes LDHA, LDHB, and LDHC is equivalent to Ldh1, Ldh2, and Ldh3, respectively.     

Creation of a clone panel of fox x Chinese hamster somatic cell hybrids and chromosome mapping of genes for LDHA, LDHB, GPI, ESD, G6PD, HPRT, alpha-GALA in the silver fox

A clone panel of fox-hamster somatic cell hybrids which can be used for fox gene mapping was set up. Analysis of patterns of chromosome-enzyme segregation made it possible to assign gene GPI to chromosome 1, LDHA to chromosome 11, LDHB to chromosome 8, ESD to chromosome 6 and G6PD, HPRT, alpha-GALA to chromosome X.     

Further data on chromosomal assignments of pig enzyme loci LDHA, LDHB, MPI, PEPB and PGM1, using somatic cell hybrids

Summary. Clear interspecies differentiation between the chromosomes in pig-mouse somatic cell hybrids was achieved by using the THA-technique for the cytogenetic analysis. The assignments of LDHB and MPI to pig chromosomes nos 5 and 7 respectively, reported previously, were confirmed by analysis of 34 hybrid clones. The LDHA, PEPB and PGM1 genes were assigned to pig chromosomes nos 2, 5 and 6 respectively. Both LDHB and PEPB were indicated to be located on the long arm, except the most proximal part, of pig chromosome no. 5. The proposed synteny between LDHB and PEPB in pigs is in accordance with the synteny observed between these two loci in several other mammalian species.     

A preliminary account of the properties of recombinant human Glyoxylate reductase (GRHPR), LDHA and LDHB with glyoxylate, and their potential roles in its metabolism

Human lactate dehydrogenase (LDH) is thought to contribute to the oxidation of glyoxylate to oxalate and thus to the pathogenesis of disorders of endogenous oxalate overproduction. Glyoxylate reductase (GRHPR) has a potentially protective role metabolising glyoxylate to the less reactive glycolate. In this paper, the kinetic parameters of recombinant human LDHA, LDHB and GR have been compared with respect to their affinity for glyoxylate and related substrates. The Km values and specificity constants (Kcat/K(M)) of purified recombinant human LDHA, LDHB and GRHPR were determined for the reduction of glyoxylate and hydroxypyruvate. K(M) values with glyoxylate were 29.3 mM for LDHA, 9.9 mM for LDHB and 1.0 mM for GRHPR. For the oxidation of glyoxylate, K(M) values were 0.18 mM and 0.26 mM for LDHA and LDHB respectively with NAD+ as cofactor. Overall, under the same reaction conditions, the specificity constants suggest there is a fine balance between the reduction and oxidation reactions of these substrates, suggesting that control is most likely dictated by the ambient concentrations of the respective intracellular cofactors. Neither LDHA nor LDHB utilised glycolate as substrate and NADPH was a poor cofactor with a relative activity less than 3% that of NADH. GRHPR had a higher affinity for NADPH than NADH (K(M) 0.011 mM vs. 2.42 mM). The potential roles of LDH isoforms and GRHPR in oxalate synthesis are discussed.     

Immunochemical evidence that the single lactate dehydrogenase of lampreys is more similar to LDHB4 than to LDHA4 of hagfish

The tetrameric lactate dehydrogenases (LDH) of vertebrates contain several different subunits that arose by gene duplication. While the A and B subunits occur in all classes of gnathostomes, the enzymes of agnathans appear to represent two stages in the evolution of vertebrate LDH. Lampreys of the family Petromyzontidae have a single enzyme classified as LDHA4, while hagfish possess both A and B subunits which form only the two homopolymers LDHA4 and LDHB4. It is generally assumed that the original vertebrate LDH was an A4 type, that duplication to give the B subunit occurred prior to the divergence of lampreys and hagfish, and that modern lampreys subsequently lost expression of the B gene. Lactate dehydrogenases were purified from representatives of all three lamprey families, and it was confirmed that members of the Mordaciidae and Geotriidae also possess single tetrameric LDH enzymes containing one subunit type. The kinetic properties of the lamprey LDH enzymes were compared with the LDH homopolymers of hagfish, skate, and sardine. These properties did not allow the lamprey enzymes to be unequivocally identified as either LDHA4 or LDHB4. Immunochemical titration using antisera against lamprey and hagfish LDH homopolymers demonstrated that the lamprey LDH enzymes showed greater immunochemical similarity to LDHB4 than to LDHA4 of hagfish. It is concluded that there is little evidence for the claim that the original vertebrate LDH was an A4 rather than B4 type.     

cDNA cloning of pig testicular lactate dehydrogenase-C, thermal stability of the expressed enzyme, and polymorphism among strains

Pig testicular lactate dehydrogenase-C (LDHC) cDNA was cloned and sequenced. The deduced sequence of 332 amino acids from pig LDHC shows 73% and 67% identity with that of pig LDHA (muscle) and LDHB (heart) respectively, whereas pig LDHA and LDHB isozymes shows 74% sequence identity. Pig and mouse LDHC cDNAs were subcloned into bacterial expression vector, and the expressed pig LDHC isozyme was shown to be as thermally stable as mouse LDHC isozyme. Pig genomic DNAs from Chinese Meishan, English Yorkshire, Danish Landrace and American Duroc were shown to exhibit polymorphic sites for restriction enzymes EcoRI, BamHI and PstI.     

Further data on chromosomal assignments of pig enzyme loci LDHA, LDHB, MPI, PEPB and PGM1, using somatic cell hybrids

Clear interspecies differentiation between the chromosomes in pig-mouse somatic cell hybrids was achieved by using the THA-technique for the cytogenetic analysis. The assignments of LDHB and MPI to pig chromosomes nos 5 and 7 respectively, reported previously, were confirmed by analysis of 34 hybrid clones. The LDHA, PEPB and PGM1 genes were assigned to pig chromosomes nos 2, 5 and 6 respectively. Both LDHB and PEPB were indicated to be located on the long arm, except the most proximal part, of pig chromosome no. 5. The proposed synteny between LDHB and PEPB in pigs is in accordance with the synteny observed between these two loci in several other mammalian species.     

Silver fox gene mapping: conserved chromosome regions in the order Carnivora

Twenty-three silver fox x hamster somatic cell hybrid clones were used to assign 15 fox genes: GPI to chromosome 1; PGD to chromosome 2; MDH2 to chromosome 3; ESD to chromosome 6; LDHB to chromosome 8; NP to chromosome 10; LDHA to chromosome 11; APRT, ENO1, and PGM1 to chromosome 12; IDH1 and MDH1 to chromosome 16; and GLA, G6PD, and HPRT to the X chromosome. High-resolution G-banding of human, cat, mink, and fox chromosomes containing homologous regions (according to genetic maps) revealed regions of putative homology. The results lend support to the suggestion that the most considerable karyotypic reorganization of the ancestral genome in the order Carnivora occurred during Canidae formation. The details of karyotypic evolution in mammals are discussed.     

ABR, an active BCR-related gene.

The human BCR gene on chromosome 22 is specifically involved in the Philadelphia translocation, t(9;22), a chromosomal rearrangement present in the leukemic cells of patients with chronic myeloid leukemia or acute lymphoblastic leukemia. In most cases, the breakpoints on chromosome 22 are found within a 5.8 kb region of DNA designated the major breakpoint cluster region (Mbcr) of the BCR gene. Hybridization experiments have indicated that the human genome contains BCR gene-related sequences. Here we report the molecular cloning of one of these loci, for which we propose the name ABR. In contrast with the other BCR-related genes studied to date, ABR represents a functionally active gene and contains exons very similar to those found within the Mbcr. Unlike the BCR gene, the ABR gene exhibits great genomic variability caused by two different variable tandem repeat regions located in two introns. All other BCR gene-related sequences isolated so far and the BCR gene itself are located on chromosome 22. In contrast, the ABR gene is located on chromosome 17p.     

Confirmed assignments of 15 structural gene loci to chromosomes of four owl monkey karyotypes

Fifteen gene loci for constitutive enzymes previously localized to specific owl monkey chromosomes of karyotypes III, V, and VI are confirmed by their assignments to homologous chromosomes of owl monkey karyotypes I, II, IV, and VII. The syntenic mapping of LDHA and GPI on a large metacentric, II-2, and the separate assignment of these two loci to two acrocentrics, I-9 and I-15, provide genetic evidence supporting the proposed fusion-fission event that characterized the karyotypic difference between owl monkeys inhabiting Colombia and the Panama Canal Zone. Moreover, the proposed hypothesis on chromosome polymorphism among the Colombian owl monkeys with karyotypes II, III, and IV, resulting from a fusion-fission event involving one metacentric and two subtelocentric pairs, is supported by the assignment of LDHB and MDH1 to the large metacentric I-2 and the separate localization of these two gene loci to II-13 and II-14, respectively.     

不同海拔牦牛骨骼肌中乳酸脱氢酶三种亚基基因表达的比较

为了阐明高原低氧对牦牛（Bos mutus）骨骼肌中乳酸脱氢酶（LDH）三种亚基基因（LDHA、LDHB和LDHC）表达的影响,本实验分别选取高海拔（4 200 m）、中海拔（3 200 m）和低海拔（1 900 m）三个海拔位置养殖的临床健康成年雄性牦牛各5头,采用实时荧光定量PCR(qRT-PCR)和蛋白质印迹法检测牦牛骨骼肌中LDH三种亚基基因的m RNA表达和蛋白表达水平。结果表明,随海拔的升高,牦牛骨骼肌中LDHA m RNA的表达逐渐下降;LDHB m RNA先降低后升高,在高海拔组牦牛中表达最高,相对表达量为2.82±0.12,与低海拔组（1.01±0.07）、中海拔组（0.73±0.06）牦牛LDHB mRNA表达量差异显著（P <0.05）;LDHC mRNA的表达量随海拔的升高呈下降趋势,且低海拔组（1.10±0.16）、中海拔组（0.86±0.16）、高海拔组（0.69±0.12）组间两两相比均差异显著（P <0.05）。LDHA和LDHC蛋白表达量随海拔的升高呈下降趋势,且LDHA蛋白表达量在低海拔组（1.00±0.00）、中海拔组（0.88±0.0...     

Defining the locus of origin of a genetically determined electrophoretic variant of a multilocus enzyme system; the calcutta-1 of human LDH system is a B-locus variant

Summary Six (four Hindus, one Sikh, and one Muslim) out of 213 individuals originating from different parts of the Indian subcontinent (namely, Andhra Pradesh, Maharashtra, Uttar Pradesh, East Punjab, and West Punjab) were found to be Calcutta-1 (CAL1) variants of lactate dehydrogenase (LDH). The CAL1 variant was originally described (and thus, generally believed at present) as an allelic variant at the LDHA locus in chromosome 11. By using an improved Cellogel electrophoretic procedure the isozyme patterns observed in the erythrocytes and leukocytes of the variant have indicated that the CAL1 is not a variant of LDHA but that of LDHB, a chromosome 12 marker. This suggestion was supported by the isozyme patterns of LDH in a set of segregating clones of man-mouse somatic cell hybrids with the variant as human partner. Moreover, the variant cosegregated consistently with the human chromosome 12 and with the markers firmly assigned to the latter but not with human chromosome 11 or its markers in these hybrids. These results confirmed that the CAL1 is an LDHB variant.     

Of rabbit and man: Comparative gene mapping

Summary Nineteen cell hybrids were obtained by fusing rabbit (Oryctolagus cuniculus, OCU) fibroblasts and a Chinese hamster cell line HGPRT. Eleven enzymatic markers were investigated for cosegregation analysis. Seven could be assigned to OCU chromosomes: LDHA to OCU1; LDHB and TPI to OCU4; PEPB, NP, and ITP to OCU16; and G6PD to OCUX. Two assignments were considered possible: MDH2 to OCU15, and GUK to OCU3 or 15. Two could not be assigned: MDH1 and PGD. These results are consistent with the OCU-HSA chromosome homocologies previously reported, except for PEPB.     

Molecular dynamics simulation of lactate dehydrogenase adsorption onto pristine and carboxylic-functionalized graphene

ABSTRACT

Lactate dehydrogenase (LDH) is a tetrameric enzyme which is composed of two subunits known as LDHA and LDHB, which are encoded by the LDHA and LDHB genes respectively. LDH catalyses the last step in anaerobic glycolysis through the reversible conversion of pyruvate to lactate via coupled oxidation of NADH cofactor. The LDHA plays an important regulatory role in anaerobic glycolysis, by catalysing the final step of the process. Therefore, it is likely that increases in the expression level of LDHA in cancer cells could facilitate the efficiency of anaerobic glycolysis. Measuring the level of serum LDHA is a key step in the diagnosis of many cancer types. In this study, the adsorption, stability, and dynamics of LDHA on the surface of pristine graphene (PG) and carboxylated graphene (COOH-Graphene) were investigated using its molecular dynamics simulation. Variations in root mean square deviation, root mean square fluctuation, solvent accessible surface area and adsorption energy of the LDHA during the simulation were calculated to analyse the effect of PG and COOH-Graphene on the overall conformation of LDHA. Results showed that the adsorption of LDHA on COOH-Graphene is mostly mediated by electrostatic interactions, whereas on the PG, both Van der Waals and π-π interactions are prominent.     

Synteny mapping in the horse using horse-mouse heterohybridomas

In a study of 35 horse-mouse heterohybridoma cell lines, synteny in the horse was found between LDHB, PEPB and IGFl and between NP, MPI and IDH2. A synteny between ADA and PEPC was also indicated. The loci for horse immunoglobulin light chain (IgL) genes and for LDHA were independent.     

Regional assignment of human genes TPI1, GAPDH, LDHB, SHMT, and PEPB on chromosome 12.

Karyological analysis was performed on a series of human-Chinese hamster cell hybrids containing deletions of human chromosome 12. Chromosome breakage was produced by treatment of the cells with either X-rays or 5-bromodeoxyuridine and near-visible light. The hybrid clones were analyzed for the presence or absence of the following five human gene markers known to be located on chromosome 12: triosephosphate isomerase-1 (TPI1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase-B (LDHB), serine hydroxymethyltransferase (SHMT), and peptidase-B (PEPB). Based on the correlation between the isozyme markers and karyological analysis of these clones, a regional map of the five human genes on chromosome 12 was established. The linear order for these genes is: pter-TPI1-GAPDH-LDHB-centromere-SHMT-PEPB-qter. The locations of these genes are: TPI1, GAPDH, LDHB: pter leads to p12; SHMT: q12 leads to q14; PEPB: q14 leads to qter. Statistical analysis similar to that of Goss and Harris (1975, 1977a, b) has been performed on the segregation data in the hybrid clones. The statistical map, in general, agrees with the cytogenetic map and further localizes PEPB to 12q21.     

New gene assignments in the baboon and new chromosome homoeologies with man

Eight new gene assignments were demonstrated in the baboon (Papio papio, PPA) by cosegregation analysis of twelve hybrid clones obtained by fusion between PPA fibroblasts and a mouse cell line deficient in thymidine kinase. The following markers and syntenic groups were assigned: SOD1 to PPA3, GLO-ME1 to PPA-4, PGM2 to PPA5, CKBB-SORD to PPA7, LDHB to PPA11 and LDHA to PPA14. These localizations are in agreement wit hthe following homoeologies with the human karyotype: PPA3-HSA21, PPA4-HSA6, PPA5-HSA4, PPA7-HSA14 and 15, PPA11-HSA12, PPA14-HSA11.     

Estrogen-Related Receptor Alpha Modulates Lactate Dehydrogenase Activity in Thyroid Tumors

Metabolic modifications of tumor cells are hallmarks of cancer. They exhibit an altered metabolism that allows them to sustain higher proliferation rates in hostile environment outside the cell. In thyroid tumors, the expression of the estrogen-related receptor α (ERRα), a major factor of metabolic adaptation, is closely related to the oxidative metabolism and the proliferative status of the cells. To elucidate the role played by ERRα in the glycolytic adaptation of tumor cells, we focused on the regulation of lactate dehydrogenases A and B (LDHA, LDHB) and the LDHA/LDHB ratio. Our study included tissue samples from 10 classical and 10 oncocytic variants of follicular thyroid tumors and 10 normal thyroid tissues, as well as samples from three human thyroid tumor cell lines: FTC-133, XTC.UC1 and RO82W-1. We identified multiple cis-acting promoter elements for ERRα, in both the LDHA and LDHB genes. The interaction between ERRα and LDH promoters was confirmed by chromatin immunoprecipitation assays and in vitro analysis for LDHB. Using knock-in and knock-out cellular models, we found an inverse correlation between ERRα expression and LDH activity. This suggests that thyroid tumor cells may reprogram their metabolic pathways through the up-regulation of ERRα by a process distinct from that proposed by the recently revisited Warburg hypothesis.     

SV40-transformed human fibroblasts exhibit a characteristic chromosomal pattern

A karyotype study of seven SV40-transformed human fibroblast cell lines was performed using R-banding. Although large variations existed from line to line and, to a lesser degree, from cell to cell in a given line, many common features were found. The most characteristic were chromosome imbalances. Some of the chromosomes or chromosome segments present in excess were, in decreasing order of frequency, the early replicating X, 12q, 3q, 12p, 19, 1p, and 6p. Losses of other chromosomes and chromosome segments were also frequent and involved 11p, 2p, 6q, 10p, 18, 4q, 8p, 4p, 10q, and 16. These imbalances seemed to correlate with metabolic characteristics, previously described, such as low activities of catalase (11p), superoxide dismutase 2 (6q), and acid phosphatase (2p, 11p) and a high ratio of lactate dehydrogenase B (LDHB, 12p) activity to LDHA (11p) activity.