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R H Goodman

Publications and source records attributed to R H Goodman.

106 records · Page 6Linked to original sources
PubMed1981

Calcitonin messenger RNA encodes multiple polypeptides in a single precursor.

Recombinant DNA techniques were used to analyze the structure of the messenger RNA encoding a precursor of calcitonin, a small calcium-regulating hormone of 32 amino acids. Analyses of the nucleotide sequences of cloned complementary DNA's comprising the entire coding sequence of the messenger RNA revealed that calcitonin is flanked at both its amino and carboxyl termini by peptide extensions linked to the hormone by short sequences of basic amino acids. The location of glycine next to the carboxyl terminal prolinamide of calcitonin is consistent with indications that glycine is required for the enzymatic amidation of proline to the prolinamide. During cellular biosynthesis, calcitonin arises from a large precursor protein by cleavages at both amino and carboxyl terminal residues of the hormone. These findings raise questions concerning the regulation of these cleavages and the potential biological functions of the precursor extensions derived from these cleavages.

Amino Acid Sequence↗
PubMed1981

Pancreatic pre-proglucagons are encoded by two separate mRNAs.

Poly(A) RNA prepared from anglerfish islets programs the synthesis in a wheat germ cell-free system of two proteins of Mr = 14,500 and Mr = 12,500 that are both immunoprecipitated by an antiserum prepared to pancreatic glucagon of Mr = 3,500 (29 amino acids). We provide evidence by cDNA hybridizations and nucleotide sequence analyses that these two proteins are precursors of glucagon and that they are encoded by separate genes. Two cloned recombinant cDNAs prepared from the islet mRNAs individually hybrid-selected mRNAs that directed the cell-free synthesis of each of the two glucagon-related proteins. Nucleotide sequence analysis of the cDNA corresponding to the Mr = 14,500 protein revealed a coding sequence for a peptide of 29 amino acids flanked by Lys-Arg sequences typical of those found at the sites of post-translational cleavages of hormone precursors. Twenty of the 29 amino acids in the sequence are identical with those found in the sequence of mammalian pancreatic glucagon. The second of the two cDNAs completely hybrid-arrested the translation of the mRNA encoding the smaller glucagon precursor of Mr = 12,500 but had no effect on the translation of the mRNA encoding the Mr = 14,500 precursor. The cDNA corresponding to this Mr = 14,500 precursor hybridized to the DNA of bacterial colonies containing the cDNA for the Mr = 12,500 precursor. Thus, two separate but partially homologous mRNAs encode the two pre-proglucagons.

Amino Acid Sequence↗
PubMed1981

Intestinal pre-prosomatostatin. Identification of mRNA coding for a precursor by cell-free translations and hybridization with a cloned islet cDNA.

Somatostatin, a tetradecapeptide hormone, is produced in numerous organs including the hypothalamus, pancreatic islets, and the gastrointestinal tract. Recently we identified two separate biosynthetic precursors of somatostatin (Mr = 16,000 and 14,000) among the cell-free translation products encoded by mRNAs prepared from the islets of the anglerfish. The nucleotide sequence of a cloned cDNA encoding the larger of the two pre-prosomatostatins revealed the sequence of the tetradecapeptide somatostatin at the COOH terminus of a polypeptide of 119 amino acids. We now have prepared poly(A)RNA from the intestine of the anglerfish and by immunoprecipitation analyses find a single somatostatin-related translation product that co-migrates during electrophoresis on sodium dodecyl sulfate-polyacrylamide gels with the larger islet pre-prosomatostatin (Mr = 16,000). Analyses of the sizes of the intestinal and islet mRNAs by agarose gel electrophoresis and hybridization with 32P-labeled cDNA containing the coding sequence for the large islet pre-prosomatostatin showed that the complementary RNA in the intestine (600 bases) is 30 nucleotides smaller than that in the islet (620-630 bases). These observations indicate that a gene encoding somatostatin is expressed in the intestine and suggest that the intestinal mRNA is distinct from the two mRNAs encoding the islet somatostatins.

Animals↗
PubMed1981

Medullary thyroid carcinoma identified by cell-free translation of tumor messenger ribonucleic acid in a patient with a neck mass and the syndrome of ectopic adrenocorticotropin.

We report a patient who presented with a lateral neck mass and Cushing's syndrome secondary to the ectopic production of ACTH. The initial diagnosis was a nonchromaffin paraganglioma based on conventional light and electron microscopic studies. However, during this patient's hospital course, we determined that mRNA extracted from the tumor directed the translation of a calcitonin precursor in a cell-free system. This finding led to a consideration of the diagnosis of medullary thyroid carcinoma, which was then confirmed by further endocrine and histological evaluations. This is a report of the identification of a tumor type using techniques of molecular biology.

ACTH Syndrome, Ectopic↗
PubMed1980

Nucleotide sequence of a cloned structural gene coding for a precursor of pancreatic somatostatin.

We have constructed and cloned, in bacteria, recombinant plasmids containing DNA complementary to mRNA coding for a pancreatic pre-prosomatostatin, a product of the cell-free translation of pancreatic islet mRNAs shown previously by immunoprecipitation to be a precursor of somatostatin. A clone containing a nearly full-length cDNA insert of 550 base pairs was identified and appeared to contain the entire coding sequence for the somatostatin precursor in addition to portions of the 5' and 3' untranslated regions. mRNA coding for the pre-prosomatostatin is 600-630 bases long as determined by agarose gel electrophoresis and hybridization with labeled cDNA. Analyses of the nucleotide sequence of the cDNA revealed a protein of 119 amino acid beginning with methionine followed by a typical leader sequence containing 18 hydrophobic amino acids. The tetradecapeptide somatostatin, identical in sequence to mammalian hypothalamic somatostatin, is located at the carboxy terminus followed immediately by a stop codon. An ARg-Lys sequence immediately preceding the sequence of somatostatin is typical of a prohormone cleavage site. A sequence Ala-Pro-Arg-Glu preceding the Arg-Lys cleavage site is identical to that found in porcine prosomatostatin. The evolutionary conservation of the identical amino acid sequence of the somatostatin tetradecapeptide from fish to mammals is remarkable. In addition, similar conservation, in fish and mammals, of the sequence Ala-Pro-Arg-Glu-Arg-Lys preceding the coding region for somatostatin suggets that this particular sequence may have biologic importance in cellular processing of the somatostatin precursor.

Amino Acid Sequence↗
PubMed1980

Glucagon precursors identified by immunoprecipitation of products of cell-free translation of messenger RNA.

Polyadenylated RNA extracted from anglerfish islets was translated in a wheat germ cell-free system containing [35S]methionine in the presence and absence of microsomal membranes prepared from a canine pancreas. Labeled translation products were analyzed by immunoprecipitation with an antiserum to porcine glucagon, followed by electrophoresis of the translation products and immunoprecipitated proteins on SDS polyacrylamide gels. In the absence of microsomal membranes two proteins of Mr = 14,500 and Mr = 12,500 were specifically immunoprecipitated with antiglucagon serum. Addition of microsomal membranes to the translation reactions resulted in a diminution of the labeled protein of Mr = 14,500 and a marked increase in the immunoreactive protein of Mr = 12,500. The protein of Mr = 12,500 was resistant to degradation by proteolytic enzymes added to translation reactions, indicating that it was segregated within microsomal vesicles. These results are consistent with synthesis of anglerfish islet glucagon in the form of a pre-prohormonal precursor (Mr = 14,500) containing a leader sequence that is cotranslationally cleaved from the protein by enzymes associated with microsomal membranes to produce a smaller intermediate prohormonal precursor (Mr = 12,500) of pancreatic glucagon (Mr = 3500).

Animals↗
PubMed1979

Eosinophilic granuloma mimicking a pituitary tumor.

The authors present the case report of a patient in whom hypopituitarism, diplopia, and visual field defects were due to eosinophilic granuloma. Radiographic studies were suggestive of a pituitary tumor and subsequent histological evaluation showed replacement of the anterior pituitary by histiocytic cells. Eosinophilic granuloma should be included in the differential diagnosis of an intrasellar mass.

Adult↗
PubMed1975

Studies on memory: inhibitors of protein synthesis also inhibit catecholamine synthesis.

The rates of accumulation of newly synthesized catecholamines and endogenous catecholamine levels in mice were determined after treatment with cycloheximide, acetoxycycloheximde, puromycin, and anisomycin. The rates of accumulation were found to be decreased by all antibiotics tested, weakening the assumption that their amnestic effects are due solely to inhibition of protein synthesis.

Animals↗
PubMed1975

The effect of acetoxycycloheximide on rate of accumulation of cerebral catecholamines from circulating tyrosine as related to its effect on memory.

The rate of accumulation of newly synthesized catecholamines and endogenous catecholamine levels in mice were determined after an amnestic intracranial dose of acetoxycycloheximide. Rates of accumulation were found to be severly decreased for a period of 12 hr after injection. Total catecholamine levels were increased from 1 to 4 hr, then decreased 17 hr following injection. These results are discussed in terms of previous behavioral observations. It is pointed out that they weaken the assumption that acetoxycycloheximide's amnestic effects are solely due to inhibition of protein synthesis.

Animals↗
PubMed1973

Cycloheximide and acetoxycycloheximide: inhibition of tyrosine hydroxylase activity and amnestic effects.

Mice and rats trained after treatment with cycloheximide or acetoxycycloheximide in a conditioned avoidance response develop an amnesia of their training experience. This amnesia has been attributed to the profound inhibition of protein synthesis caused by the two antibiotics. Evidence is presented that additionally the antibiotics inhibit the activity of tyrosine hydroxylase, a finding that suggests that their amnestic effect may be due in part to reduction of the functional pool of norepinephrine.

Acetates↗
PubMedDate not supplied

Biosynthesis of pancreatic islet hormones.

We have outlined the various strategies used to characterize the precursors of three pancreatic islet hormones--somatostatin, pancreatic polypeptide and VIP. In each case, isolation of the cDNA clones was facilitated by the use of gastrointestinal tissues that were extremely rich in specific mRNA. Characterization of the structures of the precursors is clearly only the first step in understanding the regulation of pancreatic hormone biosynthesis. It is likely that the availability of the cDNA clones will allow us to define the actual mechanisms underlying hormone production within the pancreas.

Animals↗
PubMedDate not supplied

In situ hybridization methods for the detection of somatostatin mRNA in tissue sections using antisense RNA probes.

In situ hybridization studies with [32P] and [3H] labelled antisense RNA probes were undertaken to determine optimal methods of tissue fixation, tissue sectioning, and conditions of hybridization, and to compare the relative merits of the two different radioactive labels. The distribution of somatostatin mRNA in neurons of rat brain using a labelled antisense somatostatin RNA probe was employed as a model for these studies. The highest degree of sensitivity for in situ hybridization was obtained using paraformaldehyde fixation and vibratome sectioning. Optimal autoradiographic localization of mRNA was obtained within 7 days using [32P] labelled probes. However, due to the high energy emittance of [32P], precise intracellular localization of hybridization sites was not possible. [3H] labelled RNA probes gave more precise cellular localization but required an average of 18-20 days autoradiographic exposure. The addition of the scintillator, PPO, decreased the exposure time for the localization of [3H] labelled probes to seven days. We also report a method for combined in situ hybridization and immunocytochemistry for the simultaneous localization of somatostatin in mRNA and peptide in individual neurons.

Animals↗