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J E Rall

Publications and source records attributed to J E Rall.

At least 19 recordsLinked to original sources
PubMed1995

Steroid/thyroid hormone receptor genes in Caenorhabditis elegans.

The large family of steroid/thyroid hormone receptor (STR) genes has been extensively studied in vertebrates and insects but little information is available on it in more primitive organisms. All members possess a DNA binding domain of zinc fingers of the C2, C2 type. We have used the polymerase chain reaction with degenerate oligonucleotide primers covering this region to clone three distinct members of this family from the nematode Caenorhabditis elegans. All three belong to the retinoic acid receptor (RAR), thyroid hormone receptor subfamily of genes. The cDNA of one of these clones shows such a high homology to DHR3, an early ecdysone response gene found in Drosophila, and MHR3, identified in Manduca sexta, that we have termed it CHR3. Furthermore, the C-terminal portion of the deduced protein sequence shows a box containing eight identical amino acids among CHR3, DHR3, and MHR3 suggesting an identical specific ligand for these proteins. CNR8 shows homology to NAK1, and CNR14 has homology to both the RAR-gamma 1 gene and to another ecdysone response gene, E78A. Neither of the latter two cDNAs is a clear homologue of any known gene and each is distinctive. All of these genes are expressed varyingly in both larval and adult stages of nematode development as shown by Northern blot analyses. These data demonstrate that the STR family of genes is represented in a nematode whose ancestor appeared well before the branching that gave rise to the Arthropoda and Chordata.

Amino Acid Sequence↗
PubMed1994

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Genetics↗
PubMed1989

Thyroid hormone-mediated transcriptional activation of the rat liver malic enzyme gene by dehydroepiandrosterone.

Dehydroepiandrosterone (DHEA), a naturally occurring steroid secreted from the adrenal, has been reported to decrease the body weight gain in rodents without suppressing food intake and to stimulate malic enzyme activity in liver (Tepperman, H. M., de la Garza, S. A., and Tepperman, J. (1968) Am. J. Physiol. 214, 1126-1132). Herrin, we demonstrate that DHEA induces hepatic malic enzyme activity by increasing the rate of transcription of the malic enzyme gene. This transcriptional activation of the malic enzyme gene is dose dependent, i.e. the treatment of euthyroid male rats with daily doses of 17.5 and 35 mg of DHEA/100 g of body weight for 7 days elevated the rate of malic enzyme gene transcription in liver above the basal levels 4-5- and 8-9-fold, respectively. The levels of nuclear malic enzyme RNA, cytoplasmic malic enzyme mRNA, and enzyme activity were increased correspondingly. Malic enzyme stimulation by DHEA was liver specific, i.e. malic enzyme activity in brain, heart, kidney, and testis was unchanged. Thyroid hormone is required for the induction of hepatic malic enzyme activity by DHEA since in hypothyroid animals, DHEA was without effect. However, stimulatory effects of thyroid hormone and DHEA on malic enzyme expression are additive in euthyroid rat livers at both levels of gene transcription and enzyme activity.

Animals↗
PubMed1989

Structural characterization of the rat malic enzyme gene.

We have identified and characterized lambda bacteriophage clones containing genomic DNA encoding rat malic enzyme [(S)-malate:NADP+ oxidoreductase (oxaloacetate-decarboxylating); EC 1.1.1.40]. The malic enzyme gene is unexpectedly large, spanning at least 95 kilobases. It is divided into 14 exons that range in size from 76 to 1513 base pairs. The sizes and boundaries of the exons were determined by Southern blotting and DNA sequencing. The sequences at the 5' and 3' ends of each intron conformed to the consensus sequence for mammalian introns. S1 nuclease and primer-extension assays showed that transcription of the malic enzyme gene initiates at multiple sites, the strongest one at position -31 relative to the ATG. "TATA and CCAAT box" homologies are not present in the proximal promoter region. Analysis of the 3' end of the gene showed that the utilization of alternate polyadenylylation signals in exon 14 results in two mRNAs with 3' untranslated regions of 345 and 1345 nucleotides, respectively.

Amino Acid Sequence↗
PubMed1988

Transcriptional activation and stabilization of malic enzyme mRNA precursor by thyroid hormone.

One of the responses to the administration of thyroid hormone is an increase in malic enzyme (EC 1.1.1.40) mRNA in rat liver. We have previously shown that 3,5,3'-triiodo-L-thyronine (T3) causes a 3-4-fold increase in the rate of transcription of the malic enzyme gene as determined by in vitro run-off assays with the cDNA probe following T3 treatment for 10 days (Dozin, B., Magnuson, M.A., and Nikodem, V. M. (1986) J. Biol. Chem. 261, 10290-10292). Since the level of cytoplasmic mRNA increases 10-15-fold, one or more additional mechanisms must be operative to produce the full effect. We have now analyzed the time course of the effect of T3 on the rate of transcription and the accumulation of malic enzyme RNA in the nucleus using malic enzyme cDNAs and intronic probes. There is an approximately 10-12-fold increase in the level of nuclear RNA accompanied by the same increase in cytoplasmic mRNA, showing a half-rise time of about 60 h. The 3-4-fold increase in the transcription rate occurred with a half-time of about 18 h. The relative values for either the increase in transcriptional activity or the increase in the level of malic enzyme RNA in the nucleus were identical irrespective of the probes used. As a control, we examined the effect of a high carbohydrate diet which is known to increase malic enzyme mRNA without affecting either transcriptional rate or nuclear RNA (Dozin, B., Rall, J. E., and Nikodem, V. M. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 4705-4709). As expected, no change in the level of malic enzyme RNA in the nucleus was found with the intronic probes. We conclude that T3 both activates transcription of the malic enzyme gene in rat liver and decreases the rate of degradation of pre-mRNA coding for malic enzyme.

Animals↗
PubMed1986

Tissue-specific control of rat malic enzyme activity and messenger RNA levels by a high carbohydrate diet.

In euthyroid rats fed a high carbohydrate fat-free diet for 10 days, the mass of cellular malic enzyme mRNA in liver is increased 7- to 8-fold above the basal level. Malic enzyme activity is stimulated to the same extent. This effect does not result from an increase either in the transcriptional activity of the malic enzyme gene, as determined by nuclear run-off transcription assay, or in the content of intranuclear malic enzyme RNA sequences. Mathematical modeling shows that this increase in cytoplasmic mRNA is compatible with retarded degradation of cytoplasmic mRNA. Regulation of malic enzyme by carbohydrates is liver-specific, since no response is observed in the following nonhepatic tissues: brain, heart, spleen, kidney, testis, and lung. Furthermore, the amplitude of the response in liver depends on the thyroid state of the animals, being lower (by a factor of approximately 4) in hypothyroidism and higher (12- to 15-fold) when normal animals are injected simultaneously with a daily dose of 15 micrograms of triiodothyronine per 100 g of body weight for 10 days. Since thyroid hormones regulate liver malic enzyme synthesis predominantly at the nuclear level and carbohydrates at the cytoplasmic level, the additive effect of triiodothyronine and a high carbohydrate diet on the activity of malic enzyme is readily explicable.

Animals↗
PubMed1983

The effects of thyroid hormone on in vitro phosphorylation, acetylation, and ADP ribosylation of rat liver nuclear proteins.

The effect of thyroid hormone on acetylation, phosphorylation and ADP ribosylation of rat liver nucleoproteins was studied by incubating intact nuclei with labeled precursors. Acetylation, which occurred in histones and low molecular weight proteins (less than 30,000), was depressed in nuclei from thyroidectomized animals. The administration of L-3,5,3'-triiodothyronine (T3) increased acetate incorporation to 50% over control levels. Incorporation of labeled phosphate from ATP into most proteins was decreased in nuclei from thyroidectomized animals and increased by the administration of T3. The greatest increase produced by T3 (to 140% of control values) was seen in proteins of molecular weight greater than 68,000. Nuclei from thyroidectomized animals incorporated less ADP ribose in most proteins. Both high molecular weight proteins (greater than 68,000) and low molecular weight proteins (less than 30,000) showed a further decrease in ADP ribose incorporation in nuclei from thyroidectomized rats given T3. However, a few proteins of the middle molecular weight class showed increased ADP ribose incorporation subsequent to the injection of T3. It is suggested that a generalized increase in protein synthetic rates previously noted to be caused by T3 is accompanied by increased acetylation and phosphorylation of histones and other proteins. These changes could accelerate transcription of already active genes.

Acetylation↗
PubMed1982

Thyroid hypofunction after exposure to fallout from a hydrogen bomb explosion.

Thyroid function was evaluated in the Marshallese who were accidentally exposed to fallout-containing radioiodine isotopes in 1954. Measurements of thyrotrophin (TSH, thyroid-stimulating hormone) levels and free thyroxine (T4) index (FT4I) have revealed that, among 86 persons exposed on Rongelap and Ailingnae atolls, 14 have shown evidence of thyroid hypofunction. This was first noted in some individuals about ten years after exposure. Only two of these showed clinical evidence of hypothyroidism. The most marked TSH elevations were noted in nine persons exposed when younger than 6 years, with estimated doses to the thyroid from 390 to 2,100 rad. Most of this group subsequently had surgery for removal of thyroid nodules. The remaining five cases have been noted more recently among 36 surviving adults exposed at an older age who showed no other detectable thyroid abnormalities. This group had received estimated thyroid doses ranging from 135 to 335 rad and showed modest elevation of serum TSH levels (6 to 9 microU/mL) and a slightly subnormal FT4I. No abnormalities were found in persons on Utirik who received substantially less radiation, and hypothyroidism was present in less than 1% of the control, unexposed Marshallese. The high prevalence of a thyroid hypofunction in these persons indicates that this condition, as well as thyroid nodularity, can be a delayed complication of exposure to early fallout from a nuclear explosion. The fact that a significant fraction of the radiation to the thyroid was from short-lived radioiodine isotopes (132I, 133I, 135I), as opposed to 131I, may account for the severity of the thyroid damage.

Adolescent↗
PubMed1981

Thyroglobulin interactions with thyroid membranes. Relationship between receptor recognition of N-acetylglucosamine residues and the iodine content of thyroglobulin preparations.

Bovine thyroglobulin has been subjected to sequential glycohydrolase treatment in order to define further the components of the carbohydrate chain which are important in binding of the glycoprotein to bovine thyroid membranes. Preparations of asialoagalactothyroglobulin exhibit the best binding, suggesting that exposed N-acetylglucosamine residues on the B carbohydrate chain of thyroglobulin play an important role in the interaction of thyroglobulin with the thyroid membranes. Enhanced binding of asialoagalactothyroglobulin to microsomal, lysosomal, and Golgi membranes, as well as to thyroid cells in culture, was also observed. Isopycnic rubidium chloride gradient centrifugation, a procedure used in the isolation of thyroglobulin molecules with a low iodine content, also isolates thyroglobulin molecules with a low sialic acid content and with an increased ability to interact with wheat germ agglutinin, a lectin which recognizes exposed N-acetylglucosamine residues. The studies further indicate that there is a correlation between iodine content, exposed N-acetylglucosamine residues, and the binding of thyroglobulin to thyroid membranes.

Acetylglucosamine↗
PubMed1981

Two-dimensional gel analysis of rat liver nuclear proteins after thyroidectomy and thyroid hormone treatment.

The composition of nucleoproteins in normal rat liver, in livers from thyroidectomized animals, and in thyroidectomized animals treated with 3,3',5-triiodo-L-thyronine was examined by two-dimensional gel electrophoresis. A computer program was designed to measure the relative concentrations of each protein. Approximately 500 protein subunits could be distinguished. Of these, 102 either disappeared or were markedly decreased after thyroidectomy. Shortly after administration of the thyronine (6 hr), 13 proteins reappeared and, by 24 hr, 67 additional proteins had reappeared. These changes in protein concentrations are both the greatest in number and have the largest reported as an effect of thyroid hormone. Twenty-four hr after triiodothyronine administration, some 22 proteins seen in normal liver could not be found. Two new proteins appeared in thyroidectomized rat liver nuclei. We conclude that a major and rapid effect of thyroid hormone is exerted on hepatic nucleoproteins.

Animals↗
PubMed1981

The effects of radiation on the thyroid gland: a quantitative analysis.

Radiation can cause cancer of the thyroid, and the thyroid is one of the most radiosensitive tissues. Children are much more sensitive to thyroid irradiation than are adults. The effectiveness of thyroid iodination from radioisotopes of iodine is largely a function of the half-life of the isotope. Short-lived isotopes (132I), which give a high dose rate, are essentially equivalent, rad for rad, to x-irradiation. Long-lived isotopes (131I) are one-fifth or less as effective as x-ray. Stimulation of the thyroid by TSH markedly increases the carcinogenic potential of thyroid irradiation, and inhibition of TSH stimulation probably decreases the carcinogenic effects of radiation.

Animals↗
PubMed1980

Affinity labeling of rat liver thyroid hormone nuclear receptor.

The thyroid hormone receptor from rat liver nuclei has been covalently labeled with the N-bromoacetyl derivatives of L-thyroxine (T4) and 3,3',5-triiodo-L-thyronine (T3). Displacement binding studies showed that, in the presence of 100-fold molar excess of unlabeled N-bromoacetyl-T3 or T4, binding of [125I]T3 or [125I]T4 was nearly totally inhibited. Heat inactivation of the receptor (55 degrees C for 15 min) resulted in parallel losses in the binding of T3 (95%) and N-bromoacetyl-T3 (93%). These results indicated that T3 and T4 and their bromoacetyl derivatives compete for the same binding site. The nuclear receptor showed identical behavior in high-pressure liquid chromatography (HPLC) whether bound to T3 or T4 or covalently labeled with their bromoacetyl derivatives. HPLC provided a single-step 100-fold purification of the nuclear receptor. Na-DodSO4 gel electrophoresis of the nuclear receptor labeled with N-bromoacetyl derivatives of [125I]T3 or [125I]T4 showed one major radioactive component with a molecular weight of 56,000. Furthermore, in the absence of denaturant, the nuclear receptor either bound to [125I]T3 or covalently labeled with N-bromoacetyl-[125I]T3 showed identical mobility. These results suggested that the nuclear receptor is a single polypeptide chain and binds either T3 or T4. Nuclear receptors covalently linked with N-bromoacetyl derivatives of [125I]T3 or [125I]T4 may be useful as a marker for the preparative purification of receptor.

Affinity Labels↗