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PubMed2000

Molecular analysis of the tagF gene, encoding CDP-Glycerol:Poly(glycerophosphate) glycerophosphotransferase of Staphylococcus epidermidis ATCC 14990.

Staphylococcus epidermidis ATCC 14990 produces a wall-associated glycerol teichoic acid which is chemically identical to the major wall-associated teichoic acid of Bacillus subtilis 168. The S. epidermidis tagF gene was cloned from genomic DNA and sequenced. When introduced on a plasmid vector into B. subtilis 1A486 carrying the conditionally lethal temperature-sensitive mutation tagF1 (rodC1), it expressed an 85-kDa protein which allowed colonies to grow at the restrictive temperature. This showed that the cloned S. epidermidis gene encodes a functional CDP-glycerol:poly(glycerophosphate) glycerophosphotransferase. An amino acid substitution at residue 616 in the recombinant TagF protein eliminated complementation. Unlike B. subtilis, where the tagF gene is part of the tagDEF operon, the tagF gene of S. epidermidis is not linked to any other tag genes. We attempted to disrupt the chromosomal tagF gene in S. epidermidis TU3298 by directed integration of a temperature-sensitive plasmid but this failed, whereas a control plasmid containing the 5' end of tagF on a similarly sized DNA fragment was able to integrate. This suggests that the tagF gene is essential and that the TagF and other enzymes involved in teichoic acid biosynthesis could be targets for new antistaphylococcal drugs.

Amino Acid Sequence↗
PubMed1977

Stimulation of hepatic mitochondrial alpha-glycerophosphate dehydrogenase and malic enzyme by L-triiodothyronine. Characteristics of the response with specific nuclear thyroid hormone binding sites fully saturated.

Experiments were designed to analyze the relationship of a single i.v. dose of triiodothyronine (T3), the level of plasma and hepatic nuclear T3 attained, and the tissue response as reflected in increased activity of hepatic mitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) and cytosol "malic enzyme" (ME). These studied were carried out in euthyroid rats by varying the dose of T3 injected and the time at which the animals were killed and the enzyme levels measured. The plasma T3 concentration was determined and the fraction of nuclear sites occupied at any time t was calculated from the known plasma:nuclear relationship. As a first step, the analysis was confined to the limiting situation in which all nuclear sites were effectively saturated. The following additional information was required and obtained: A proportional relationship between the half-neutralizing volume of a specific antiserum to malic enzyme and the activity of malic enzyme was established, thus confirming previous reports that the increase in enzyme activity induced by T3 is due to increased enzyme mass. The absolute refractory period immediately after i.v. injection of T3, during which no enzyme response could be detected, was determined. This was shown to be 13.4 h for alpha-GPD and 8.2 h for ME. Lastly, the t1/2 of the enzyme decay after pulse injection of T3 was measured. This was similar for both enzymes, 2.8+/-0.6 (SD) days for alpha-GPD and 2.7+/-0.6 (SD) days for ME. The results of these studies indicated that the extent of hepatic response appears limited by full occupancy of a set of intracellular receptor sites by T3 which is in rapid equilibrium with the plasma hormone pool. The kinetic properties of the receptors, as functionally defined in these studies, resemble those associated with the recently described specific nuclear T3 sites. These data per se are thus compatible with but do not prove a nuclear site of initiation of hormone effect. Thye do allow the development of an internally consistent mathematical model which permits prediction of enzyme response when the receptor sites are fully occupied for a given length of time after the i.v. injection of hormone. A separate series of studies was carried out in thyroidectomized rats. The response characteristics of alpha-GPD were similar to those observed in euthyroid animals. In contrast, however, the early response of ME to pulse injections of T3 was very much reduced in hypothyroid animals as compared to euthryoid animals in which nuclear sites were saturated for comparable periods. These findings raise the possibility that a factor required for the induction of malic enzyme but not alpha-GPD is deficient in the hypothyroid state.

Animals↗
PubMed1984

Response of hepatic mitochondrial alpha-glycerophosphate dehydrogenase and malic enzyme to constant infusions of L-triiodothyronine in rats bearing the Walker 256 carcinoma. Evidence for divergent postreceptor regulation of the thyroid hormone response.

To characterize the hepatic response to L-triiodothyronine (T3) in an experimental nonthyroidal disease, we determined the activity of hepatic mitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) and cytosol malic enzyme (ME) as a function of the saturation of the nuclear T3 receptor during constant T3 infusions in rats bearing the Walker 256 carcinoma. Groups of control and tumor-bearing rats were infused by minipumps (Alza Corp., Palo Alto, CA) with vehicle, 1.2 or 4.5 micrograms T3/100 body wt per day for 3 d. The range for serum T3 was 47.2 +/- 4.1 to 165 +/- 17.3 ng/dl for the control rats and 13.2 +/- 1.3 to 135 +/- 14.3 ng/dl for the tumor-bearing rats. Nuclear T3 receptor concentration was between 0.41 +/- 0.06 and 0.47 +/- 0.02 ng/mg DNA in control rats and was decreased in tumor-bearing rats to between 0.23 +/- 0.03 and 0.26 +/- 0.03 ng/mg DNA. Nuclear T3 receptor concentrations were not influenced by the T3 infusions. Specifically bound nuclear T3, determined by radioimmunoassay of extracts of isolated nuclei, was decreased nearly 50% in the tumor-bearing rats. However, the calculated percentage saturation of the T3 nuclear receptor remained similar in control and tumor-bearing rats at each level of T3 infusion. Dose-response curves for alpha-GPD and ME were curvilinear and showed an exponential increase in enzyme activity with progressive receptor saturation. In tumor-bearing rats, the activity curves or calculated appearance rate curves for alpha-GPD were shifted significantly upward and to the left, indicating greater sensitivity to T3, and those of ME were shifted downward and to the right, indicating decreased responsiveness to T3. Our findings suggest that cellular factors result in postreceptor amplification of the alpha-GPD response and diminution of the ME response to T3 in tumor-bearing rats. Augmentation of the alpha-GPD response may be a prototype for other hormonal responses that enable the tumor-bearing rat to maintain an apparent euthyroid state in association with decreased serum T3.

Animals↗
PubMed1983

Effect of 5,5'-diphenylhydantoin on the activities of hepatic cytosol malic enzyme and mitochondrial alpha-glycerophosphate dehydrogenase in athyreotic rats.

Since 5,5'-diphenylhydantoin (DPH) decreases specific nuclear receptor binding of T3, the possibility that DPH might affect thyroid activity was examined by measurement of the activity of rat hepatic cytosol malic enzyme (ME) and mitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) after DPH administration. Groups of athyreotic rats, prepared by thyroidectomy and 131I administration, were injected with vehicle (V), DPH, T3, or a combined dose of DPH and T3 for 48 h. The rats were then killed, and liver fractions were prepared for the measurement of ME and alpha-GPD activities. Compared with the V group, DPH treatment resulted in a significant increase in mean ME activity in four experiments; the mean ME activity for all studies was 2.2-fold greater than that of the V group (P less than 0.001). A significant increase in mean alpha-GPD activity was not observed in DPH-treated rats. T3 treatment resulted in a mean 31.5-fold increase in ME activity and a 10.9-fold increase in alpha-GPD activity. The magnitude of T3 induction of both enzymes was substantially attenuated by simultaneous injection of DPH, to 54-66% of the activity induced by T3 alone (P less than 0.001). Pair-feeding a T3-injected group and the DPH plus T3 group did not result in a decrease in the activity of either enzyme. Moreover, the observed changes did not appear to result from alterations in enzyme determinations or from significant changes in cytosol or mitochondrial protein concentration, cytosol T3, or plasma glucose. Although DPH-induced changes in the fractional rate of enzyme metabolism cannot be excluded, it is possible that changes in enzyme activities observed after DPH injection resulted from an interaction between DPH and the nuclear T3 receptor. If so, based on the effects observed in the present studies, DPH might be classified as a partial thyroid agonist.

Animals↗
PubMed1988

Response of hepatic mitochondrial alpha-glycerophosphate dehydrogenase and malic enzyme to 3,5,3'-triiodothyronine in streptozotocin-diabetic rats.

Hepatic mitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) and cytosolic malic enzyme (ME) response to a single injection of a receptor-saturating dose of T3 were measured 10, 20, and 30 days after diabetes induction, and compared with values in controls either fed ad libitum (C) or under a restricted diet (FR). An insulin-treated diabetic (D + I) group was also included. Basal enzyme levels as well as enzyme response to T3 injection were correlated with nuclear T3 content, maximal nuclear T3-binding capacity (MBC) and equilibrium association constant (Ka). Diabetes for 10, 20, and 30 days was associated with a progressive decrease in the MBC; the mean decrease was 17%, 50%, and 59%, respectively, from the corresponding C values. The MBC in FR animals did not change appreciably during the experimental period. Moreover, neither the decreased MBC in D groups nor MBC in C, FR, or D + I animals were influenced by T3 injection. The Ka values were comparable in all experimental groups. Specifically bound nuclear T3 was decreased within the experimental period between 33% and 73% in D rats and 6% and 39% in FR rats respect to C values. T3 injection raised the mean nuclear T3 content in all groups. However, at each time interval the mean values of the nuclear T3 in D groups was significantly lower than that in C, FR, or D + I groups after T3 injection. The basal alpha-GPD activity tended to be relatively stable during the experimental period in both D and FR rats, whereas ME activity in D and FR groups was decreased, respectively, 52-64% and 18-39% from C values. The response of both alpha-GPD and ME to T3 injection in FR rats was comparable to that of C groups. The alpha-GPD response to T3 in D rats was not different from that of C rats on days 10 and 20 of the experiment, but on day 30 it decreased by 26%. In contrast, the induction of ME by T3 was severely decreased (by 66-88% of C values) within the experimental diabetes period. Thus, the measurements made in FR rats excluded the possibility that the quantitative changes in the enzyme response to T3 in D rats were nutrition-dependent. The differences between the response of alpha-GPD and ME to T3 in D rats suggest that cellular factors play a role in inhibiting or increasing the response to a given concentration of the T3-receptor complex.

Animals↗
PubMed1990

Increase in hepatic mitochondrial alpha-glycerophosphate dehydrogenase activity after surgical stress in hyperthyroid rats.

We have established a rat model to investigate the relationship among serum thyroid hormones, nuclear iodothyronine receptors, and biological responses in thyrotoxic and euthyroid rats after surgical stress. Euthyroid or hyperthyroid rats (1.0 microgram T3/ml drinking water for 14 days) were subjected to surgical stress (ether anesthesia, laparotomy plus 50 mg talc, ip). Groups of control or stressed rats were killed 1, 2, and 3 days after surgical stress for measurement of thyroid hormone-responsive hepatic enzymes, alpha-glycerophosphate dehydrogenase (alpha GPD) and cytosol malic enzyme, serum T3, T3 nuclear receptors, and GH mRNA. Thyrotoxic rats had a 3.8-fold increase in alpha GPD compared to euthyroid rats before surgical stress; alpha GPD increased further to 5.9-fold the euthyroid value 1 day after surgery (P less than 0.001) to 5.1-fold after 2 days (P less than 0.05) and was similar to control after 3 days. Malic enzyme activity increased 10.5-fold before surgical stress and decreased slightly after surgical stress perhaps due to multifactorial regulation of that enzyme. No increases in T3 nuclear receptor or GH mRNA occurred after surgery in hyperthyroid rats or in any of the above parameters after surgical stress in euthyroid rats. Our findings suggest that increased alpha GPD after surgical stress in thyrotoxic rats was not due to either increased serum total T3 or free T3 or to increased T3-nuclear receptor complexes. Increased alpha GPD, therefore, appeared to be a consequence of postreceptor amplification of this thyroidal response.

Animals↗
PubMed2001

Identification and functional analysis of mutations in FAD-binding domain of mitochondrial glycerophosphate dehydrogenase in caucasian patients with type 2 diabetes mellitus.

Ca2+-responsive mitochondrial FAD-linked glycerophosphate dehydrogenase (mGPDH) is a key component of the pancreatic beta-cell glucose-sensing device. The purpose of this study was to examine the association of mutations in the cDNA coding for the FAD-binding domain of mGPDH and to explore the functional consequences of these mutations in vitro. To investigate this association in type 2 diabetes mellitus, we studied a cohort of 168 patients with type 2 diabetes and 179 glucose-tolerant control subjects of Spanish Caucasian origin by single-stranded conformational polymorphism analysis. In vitro site-directed mutagenesis was performed in the mGPDH cDNA sequence to reproduce those mutations that produce amino acid changes in a patient with type 2 diabetes. We detected mutations in the mGPDH FAD-binding domain in a single patient, resulting in a Gly to Arg amino acid change at positions 77, 78, and 81 and a Thr to Pro at position 90. In vitro expression of the mutated constructs in Xenopus oocytes resulted in a significantly lower enzymatic activity than in cells expressing the wild-type form of the enzyme. Our results indicate that although mutations in the mGPDH gene do not appear to have a major role in type 2 diabetes mellitus, the reduction in mGPDH enzymatic activity associated with the newly described mGPDH mutations suggests that they may contribute to the disease in some patients.

Aged↗
PubMed1979

[Increased liver nuclear triiodothyronine-receptors associated with mitochondrial alpha-glycerophosphate dehydrogenase activity in hyperthyroid rats (author's transl)].

The effects of triiodothyronine (T3) on binding characteristics of nuclear T3-receptors were examined in rats. The T3-receptors were extracted by 0.4M KCl from the liver nuclei isolated from the following 3 groups of rats: (1) thyroidectomized, (2) thyroidectomized and treated with 230 ng T3/100 g body weight/day for 3 days, and (3) thyroidectomized and treated with 40 micrograms T3/100 g body weight/day for 3 days. Their association constant (Ka) and maximal binding capacity (Cmax) for T3 were determined by Scatchard analyses with and without correction for endogenous T3. The amount of endogenous T3 bound to the nuclear extracts was estimated on the basis of a specific activity of [125I]-T3 injected 2 hours before sacrifice. It was demonstrated that Cmax values corrected for the endogenous T3 were 2.5 times greater in severely hyperthyroid than in hypothyroid rats. By contrast, corrected values for Ka remained unchanged in all 3 groups of rats, although uncorrected values were apparently decreased in the severely hyperthyroid rats. Validity of the correction was supported by the in vitro experiments preincubated with stable T3. The yields of nuclear protein-125I-T3 complex in the procedure of extraction and the contents of DNA per g of liver were nearly the same in the 3 groups. The increase in Cmax of the nuclear receptors was directly related to mitochondrial alpha-glycerophosphate dehydrogenase activity. The results obtained indicate that the Cmax of nuclear T3-receptors is increased in a severely hyperthyroid state, related to hormonal action, and that the correction for endogenous T3 is essential for an accurate estimation of Ka and Cmax.

Animals↗
PubMed1979

[Sequential changes in the nuclear triiodothyronine receptors and mitochondrial alpha-glycerophosphate dehydrogenase activity after the administration of triiodothyronine (author's transl)].

The dynamics of the induction of nuclear triiodothyronine (T3)-receptors and mitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) were studied in rat liver after a single injection of a large amount of T3. The maximal binding capacity (Cmax) and association constant (Ka) of the nuclear receptors were determined by Scatchard analyses with and without correction for endogenous T3 measured by radioimmunoassay. It was demonstrated that the administration of T3 induced sequential increases in the number of nuclear T3-receptors and alpha-GPD activity in the liver. The nuclear receptors were rapidly increased to 2.5 times the hypothyroid level and thereafter decreased with a half-life of about 2 days. A parallel change in alpha-GPD activity was noted after a lag period. The total amount of extracted nuclear proteins in the liver was increased 3 days after the administration of T3. It seems likely, therefore, that the T3-induced increase in nuclear receptors is responsible, at least in part, for the induction of this enzyme. The possibility is also suggested that the nuclear receptors may be a nonhistone protein selectively synthesized in an early stage of the hormonal stimulation. Following the injection of T3, marked changes in apparent Ka were seen when no correction was made for the amount of endogenous T3 bound to the extracted nuclear proteins. With the correction, however, Ka remained the same despite the changes in the nuclear receptors and enzyme activity. The results obtained provide further evidence for the hormonal modulation of the nuclear receptors which is closely linked with the hormonal effect.

Animals↗
PubMed1975

Effect of the exposure to cold on the extrathyroidal conversion of L-thyroxine to triiodo-L-thyronine, and on intramitochondrial alpha-glycerophosphate dehydrogenase activity in thyroidectomized rats on L-thyroxine.

Thyroidectomized rats have been injected daily with 125-I labelled L-thyroxine (T4) and, once isotopic equilibrium was attained, divided into cold-exposed (4-10 degrees C) and control (21-24 degrees C) groups, the daily T4 administration being continued till the end of the experiment. Fourteen days after onset of cold exposure, the total I of different organs and of the carcass was determined and the tissues submitted to extraction and paper chromatography for the separation of T4 and T4-derived I-containing compounds. The Activity of intramitochondrial alpha-glycerophosphate dehydrogenase (alpha-GPD) was measured in kidneys and liver. It was found that the total amount of I was intensely decreased in all samples from cold-exposed animals. The proportion of this Iwhich was non-extractable was the same, in all tissues, for cold-exposed and control rats. The % of extractable tissue radioactivity in the form of T4 was decreased, and that found as T4-derived T3 was increased, in all samples from cold-exposed animals. The T3/T4 ratio was increased more than two-fold in all tissues studied. The concentration of T4 decreased significantly in all tissues, whereas the concentration of T3 in tissues of cold-exposed rats did not decrease. It actually increased in kidneys and lungs, and remained the same in liver and carcass. Despite the decrease in the concentration of T4 in the kidneys, alpha-GPD activity was increased in this tissue, where the concentration of T3 was increased. No change in the alpha-GPD activity was found for the liver, where the concentration of T3 was the same for cold-exposed and control rats. Thus, it appears likely that the conversion of T4 AND T3 is increased by the exposure to cold of thyroidectomized rats on a constant dose of T4.alpha-GPD activity in a given tissue appears to be more closely related to the concentration of T3, than to that of T4.

Animals↗
PubMedDate not supplied

alpha-glycerophosphate dehydrogenase activity in flight muscles of triatomine bugs Panstrongylus megistus and Triatoma sordida.

The alpha-glycerophosphate dehydrogenase (alpha-GPDH) activity in flight muscles of Panstrongylus megistus and Triatoma sordida, vectors of Chagas disease in Brazil, was studied. Both species showed higher enzymatic activities in fliers than in non-fliers insects. T. sordida exhibited a higher proportion of flier insects than P. megistus. A possible role of alpha-GPDH on triatomines flight is discussed.

Animals↗
PubMed1994

Palmitate esterification and glycerophosphate acyltransferase activity in adipose tissue of growing lambs.

The purposes of this study were to determine the effects of BW in growing lambs on rates of palmitate esterification (PE) and activity of glycerophosphate acyltransferase (GPAT) in subcutaneous and intermuscular adipose tissue in vitro and to determine the relationship between these in vitro measurements and carcass lipid accretion. At 37, 49, 60, and 71 kg of live weight, nine, nine, eight, and seven Columbia-Rambouillet-cross ewe lambs, respectively, were slaughtered and adipose tissue was dissected for glycerolipid biosynthesis assays. One-half of each carcass was boned, and carcass soft tissue lipid was measured. In both adipose tissues, PE and GPAT activity were highest at 37 kg (P = .0001); the greatest accumulation of carcass fat occurred between 37 and 49 kg (P = .0001). Differences in PE and GPAT were less well marked between 49-, 60-, and 71-kg lambs, but both were generally decreased with increased BW. Significant R2 from regressions of mass and percentage of carcass fat on either PE, GPAT, or steady-state glycerolipid synthesis (GLS) were from .39 to .44 (PE), .40 to .58 (GPAT), .50 to .75 (GLS), and .60 to .77 (PE, GPAT, and GLS combined). Changes in PE, GPAT, and GLS with BW were consistent with changes in rates of carcass fat accretion, which indicated a close relationship between glycerolipid biosynthesis in vitro and lipid deposition in vivo in growing-finishing lambs.

Adipose Tissue↗
PubMedDate not supplied

Gestational variation of glycerophosphate acyltransferase activity in maternal guinea pig lung and possible role of thyroid hormone in its de novo synthesis.

We have observed earlier that the pattern of gestational variation of microsomal glycerophosphate acyltransferase (GAT) activity is similar in maternal and fetal guinea pig lung. Furthermore, there is a close resemblance between these patterns and that of the gestational variation of fetal plasma thyroid hormone. It is known that triiodothyronine (T3) injected to pregnant rats can cross the placenta to some extent and cause an increase in phosphatidylcholine synthesis in fetal lung. It is possible, therefore, that the gestational increase of GAT activity in maternal and fetal lung is associated with an increase in maternal plasma thyroid hormone. The objective of this study was to investigate whether intramuscular injection of T3 to adult guinea pig causes any change in the activity of GAT in lung and, if so, to determine the mechanistic basis. The results indicated that T3 significantly increased the GAT activity in the microsomes but not in the mitochondria. Actinomycin D or cycloheximide abolished the hormone-mediated stimulation of the enzyme in the microsomes, suggesting that T3 is involved in both transcriptional and translational pathways of GAT synthesis. We also confirmed our previous preliminary finding that there is a gestational variation of GAT activity in maternal guinea pig lung and furthermore the increase in GAT activity during pregnancy is predominantly in the microsomes.

Animals↗
PubMed1975

Alpha-Glycerophosphate dehydrogenase (insoluble) and lactic dehydrogenase activities in the skeletal muscles of two insects.

The flight muscle preparations of the dragonfly Pantala flavescens and the aquatic beetle Cybister confusus showed extremely low levels of lactic dehydrogenase activity and high levels of alpha-glycerophosphate dehydrogenase (insoluble) activity. The activities of these two enzymes in the leg muscle of the beetle were approximately the same (1:1), but lactic dehydrogenase activity was several times higher than that in the flight muscles of both Insects. These results have been interpreted as indicating the high energy-yielding demands of the flight muscles during continuous sustained activity, while the leg muscles of the beetle which are involved in swimming activity derive their energy predominantly through anaerobic glycolysis.

Animals↗
PubMed1983

Increases in dihydronicotinamide adenine dinucleotide (NADH) content and alpha-glycerophosphate dehydrogenase activity in epidermal wound healing.

Alterations in NADH content and NAD-dependent dehydrogenase activity were determined in regenerating epithelium during wound healing in young guinea pigs. Regenerating epithelium exhibited increased levels of NADH. The migratory and proliferative phases of epidermal wound healing were characterized by increases in glycolytic enzyme activities, including an increase in lactate dehydrogenase (LDH). The maturation phase of epidermal wound healing was characterized by a maximal increase in alpha-glycerophosphate dehydrogenase (GOPDH) activity. The contrasting changes in LDH and GOPDH activity suggest that increased levels of NADH are utilized first by LDH in glycolysis during epidermal migration and proliferation and then by GOPDH in triacylglycerol synthesis during epidermal differentiation.

Animals↗
PubMed1999

Dexamethasone-induced changes in FAD-glycerophosphate dehydrogenase mRNA, content and activity, and insulin release in human pancreatic islets.

Human pancreatic islets were cultured for 63 hr at 2.8 or 16.7 mM D-glucose in the absence or presence of dexamethasone. In the 1.0 to 10 microM range, dexamethasone caused a concentration-related decrease in the FAD (flavin adenine dinucleotide)-linked mitochondrial glycerophosphate dehydrogenase (mGDH) mRNA content of the islets, and decreased both the mGDH content of the islets and the catalytic activity of the enzyme in islet homogenates, these effects being often more marked in islets cultured at 16.7 mM, rather than 2.8 mM, D-glucose. Even after culture in the presence of no more than 10 nM dexamethasone, namely under conditions in which the mGDH mRNA content and activity were both virtually unaffected, the corticosteroid restored the capacity of the beta-cells to display an increase in insulin output in response to a rise in D-glucose concentration in islets first cultured at 2.8 mM D-glucose but suppressed the insulinotropic action of the hexose in islets first cultured at 16.7 mM D-glucose. Whilst revealing an untoward effect of high concentrations of dexamethasone upon mGDH mRNA, content and activity in human islets, these findings also document a dual effect of a low concentration of the corticosteroid (10 nM) upon the secretory responsiveness of human islets to D-glucose, independently of any significant change in mGDH gene expression. It is proposed that such a dual action may account, in part at least, for both the well known increase in insulin output found in hypercorticism and the more recently discovered unfavourable direct effect of corticosteroid hormones on the secretory activity of islet beta-cells.

Adult↗
PubMed1991

[Cloning and inactivation of a chromosomal copy of the imidazole glycerophosphate dehydratase (HIS) gene from Hansenula polymorpha].

A gene for imidazole glycerophosphate dehydratase (HIS) has been selected from the library of Hansenula polymorpha genes by complementation of Escherichia coli hisB mutations or his3 mutation of Saccharomyces cerevisiae. Inactivation of the gene in Hansenula polymorpha strain 48V, as well as Leu(-)-Leu+ conversion of phenotype and arising of antibiotic G418 resistance resulted from transformation of the strain by the linear DNA molecules of the cloned HIS-gene with the in vitro inserted LEU2 gene from Saccharomices cerevisiae and KmR gene. The Southern hybridization analysis of the Leuf+His- G418R clones representing 1-2% of transformants population together with the DNA analysis of the monospore clones from the hybrid Leu+His-G418R transformant tetrad and tester strain have revealed the locus specific nature of the clones.

Autoradiography↗