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J F Battey

Publications and source records attributed to J F Battey.

At least 73 records · Page 4Linked to original sources
PubMed1993

Receptor-activated currents in mouse fibroblasts expressing transfected bombesin receptor subtype cDNAs.

BALB/c 3T3 cells do not normally express receptors for bombesin-like peptides [bombesin (Bn), gastrin-releasing peptide (GRP), and neuromedin B (NmB)]. Transfection of BALB/c 3T3 cells with complementary DNA-encoding GRP receptors or NmB receptors leads to stable expression of functional GRP receptors (GRP Rt) or NmB receptors (NmB Rt), respectively, which are coupled to cell membrane ion channels. Whole cell current analysis using patch electrodes shows that the activation of these newly expressed receptors induces cation conductance increases, most frequently a Ca(2+)-activated plasma membrane K+ conductance. The dose-response (peak-current) relations of both transfected receptor subtypes were sigmoidal and exhibited threshold activation concentration in the picomole range and the saturation of responses to higher concentrations than 10(-8) M. The GRP Rt responded about equally to GRP, NmB, and Bn when compared at equimolar levels, despite their known difference in binding affinity for the three peptides (GRP, Bn > NmB). In contrast, for the NmB Rt, the NmB was more potent than GRP or Bn. Among four GRP/Bn-receptor antagonists tested, the [D-Phe6]Bn(6-13) ethyl ester suppressed GRP Rt responses at low concentrations (10(-7) M). N-acetyl-GRP-(20-26) amide, [Leu13-psi(CH2NH)-Leu14]Bn, and [D-Arg1,D-Phe5,D-Trp7,9,Leu11]substance P also blocked GRP Rt responses but at higher concentrations (10(-5) M). However, at these concentrations, these four antagonists had little effect on NmB Rt responses, thereby showing a specificity of these antagonists for the GRP receptors.

3T3 Cells↗
PubMed1993

Discovery of a novel class of neuromedin B receptor antagonists, substituted somatostatin analogues.

Bombesin-related peptides have widespread activities in the central nervous system and peripheral tissues. Recent studies show two subtypes of receptors; a gastrin-releasing peptide (GRP) receptor subtype and a neuromedin B (NMB) receptor subtype exist. In contrast to the GRP receptor, no antagonists exist for the NMB receptor. In the present study we report that certain somatostatin (SS) octapeptide analogues function as selective NMB receptor antagonists. The most potent analogue, D-Nal-Cys-Tyr-D-Trp-Lys-Val-Cys-Nal-NH2, inhibited binding of 125I-[D-Tyr degree]NMB to NMB receptor-transfected 3T3 cells and C6 cells. This analogue had 100-fold lower affinity for GRP receptors. Structure-function studies were performed by synthesizing 18 structurally related SS octapeptide analogues; each of these analogues, but not native SS-14 or SS-28, also inhibited binding to NMB receptors. The stereochemistry at positions 1, 2, 7, and 8, the hydrophobicity and ring size of the substitution in positions 1, 3, and 4, and the basicity of the group in position 5 were all important in determining NMB receptor affinity. No SS octapeptide analogue increased [3H]inositol phosphates in NMB receptor-transfected cells; however, each analogue inhibited NMB-stimulated increases. The most potent analogue, D-Nal-Cys-Tyr-D-Trp-Lys-Val-Cys-Nal-NH2, caused a parallel rightward shift of the NMB dose-response curve, the Schild plot slope was not significantly different from unity, and the affinity was 230 nM. SS octapeptide analogues also interacted with SS receptors and mu-opioid receptors; however, there was no correlation between the affinities of the analogues for these receptors and their affinities for NMB receptors, demonstrating that these activities can be separated. The results demonstrate for the first time a class of antagonists with > 100-fold selectivity for NMB versus GRP receptors. Because the structural requirements for determining NMB, SS, and mu-opioid receptor activity differ, it is likely that highly selective, specific, high affinity NMB receptor antagonists can now be developed that will be useful in defining the role of NMB in various physiological processes.

3T3 Cells↗
PubMed1992

Neuronal cdc2-like kinase: a cdc2-related protein kinase with predominantly neuronal expression.

Recent studies have shown that there exists a family of protein kinases structurally and functionally related to the yeast cell cycle regulatory kinase cdc2 [Meyerson, M., Faha, B., Su, L.-K., Harlow, E. & Tsai, L.-H. (1991) Cold Spring Harbor Symp. Quant. Biol. 56, 177-186 and Meyerson, M., Enders, G. H., Wu, C.-L., Su, L.-K., Gorka, C., Nelson, C., Harlow, E. & Tsai, L.-H. (1992) EMBO J. 11, 2909-2917]. Two members of cdc2 family, p34cdc2 (also named cdk1) and cdk2, have been identified in mammalian cells. cdk1 kinase regulates the progression from G2 to M phase, and cdk2 kinase has been proposed to regulate the progression from G1 to S phase. In this work, we have cloned and structurally characterized a third member of the cdc2 kinase family with 58% amino acid sequence identity to mouse cdk1 and 61% identity to human cdk2. We call this kinase neuronal cdc2-like kinase (nclk) because, in contrast to either cdk1 or cdk2, nclk is expressed at high levels in terminally differentiated neurons no longer in the cell cycle. Previous studies have shown [Hisanaga, S., Kusubata, M., Okumura, E. & Kishimoto, T. (1991) J. Biol. Chem. 266, 21798-21803 and Guan, R. J., Hall, F. L. & Cohlberg, J. A. (1992) J. Neurochem. 58, 1365-1371] that cdk1 kinase, but not other structurally defined protein kinases, could phosphorylate the repeated Lys-Ser-Pro (KSP) motifs found in mammalian high and middle molecular mass neurofilament subunits in vitro, but the precise molecular nature of the endogenous neuronal KSP kinase has remained undefined. The structural similarity of nclk to cdk1 kinase and its high level of expression in terminally differentiated neurons suggest that nclk may play a role in the phosphorylation of the neurofilament KSP repeats in vivo, a function distinct from cell cycle regulation.

Amino Acid Sequence↗
PubMed1992

Activation of neuromedin B-preferring bombesin receptors on rat glioblastoma C-6 cells increases cellular Ca2+ and phosphoinositides.

Recent cloning studies confirm the presence of two subtypes of bombesin (Bn) receptors. In contrast to the gastrin-releasing peptide (GRP)-preferring subtype, which has been widely studied, nothing is known about the cellular mechanisms of the neuromedin B (NMB)-preferring subtype, which occurs widely in the central nervous system and gastrointestinal tissues, partially because of the lack of a cell line with functional receptors. In the present study we have investigated Bn receptors on the rat glioblastoma cell line C-6, reported to contain mRNA of the NMB receptor subtype. Binding of 125I-[D-Tyr0]NMB to these cells was time- and temperature-dependent, saturable, reversible, and only inhibited by Bn receptor agonists or antagonists. For Bn receptor agonists the relative potencies were: NMB (1.7 nM) approximately equal to litorin (3 nM) greater than ranatensin (8 nM) greater than Bn (19 nM) greater than neuromedin C (NMC) (210 nM) greater than GRP (500 nM). These relative affinities were almost identical to those for the NMB receptor subtype on rat oesophageal tissue and for Balb 3T3 cells stably transfected with the NMB receptor subtype. These potencies differed from those for the GRP receptor subtype on rat pancreatic acini [Bn approximately equal to litorin (4 nM) greater than ranatensin, NMC, GRP (15-20 nM) much greater than NMB (351 nM)]. The relative potencies of four different classes of Bn receptor antagonists were compared. Results from C-6 tumour cells agreed closely with those for binding to the NMB receptor subtype on rat oesophageal tissue and in Balb 3T3 cells stably transfected with this receptor, and differed markedly from those for binding to the GRP receptor subtype on rat pancreatic acini. Four Bn receptor antagonists had a higher affinity for the GRP subtype ([D-Phe6]Bn-(6-13)ethyl ester (500 x), [D-Phe6][psi 13-14,Cpa14]Bn- (6-14) (70 x) (where psi 13-14 refers to the replacement of the -CONH- peptide bond between Leu13 and Met14 by -CH2NH2) [psi 13-14,Leu14]Bn, [D-Phe6]Bn-(6-13) propylamide (30 x)] and two had a higher affinity for the NMB subtype on C-6 cells and transfected cells ([D-Pro4,D-Trp7,9,10] substance P-(4-11) (9 x) and [Tyr4,D-Phe12]Bn (18 x)]. In C-6 tumour cells, Bn receptor agonists caused an increase in cytosolic Ca2+ and the generation of inositol phosphates. For both responses, NMB was more than 50-fold more potent than GRP. Neither NMB nor GRP increased cyclic AMP. These results demonstrate that the rat glioblastoma cell line C-6 possesses functional NMB-preferring Bn receptors, and agonist occupation activates phospholipase C, thus increasing cytosolic Ca2+ and inositol phosphate formation. Because the interaction of Bn-related peptides with C-6 cell receptors is identical with that reported in other tissues containing the mRNA for the NMB subtype, this cell line should prove useful in exploring further the cellular basis of action of the peptides that interact with this receptor in the central nervous system and various other tissues.

3T3 Cells↗
PubMed1992

Regulation of chlorophyll apoprotein expression and accumulation. Requirements for carotenoids and chlorophyll.

Chlorophyll apoprotein accumulation and expression were examined in mutants of Chlamydomonas reinhardtii blocked at specific steps of carotenoid or chlorophyll synthesis. In the absence of carotenoids: 1) apoproteins of the core and light-harvesting complexes of photosystem I (CCI and LHCI, respectively) and photosystem II (CCII and LHCII, respectively) do not accumulate; 2) mRNAs for the CCI, CCII, and LHCII apoproteins accumulate to normal levels; and 3) synthesis of the chlorophyll apoproteins is differentially affected, or in some cases, not affected. In the absence of chlorophylls: 1) the apoproteins fail to accumulate; 2) mRNA levels for CCI and CCII apoproteins are relatively unchanged; 3) levels of LHCII apoprotein mRNA, but not rates of LHCII mRNA synthesis, are reduced in a light-dependent chlorophyll-synthesis mutant (ya12); and 4) synthesis of chlorophyll apoproteins is differentially affected or not affected in the case of several chloroplast-encoded apoproteins. These results demonstrate a direct role for carotenoids as well as chlorophylls in the stabilization of certain chlorophyll apoproteins and, for others, possibly in their translation. The data also indicate a role for chlorophyll synthesis in the stability of LHCII mRNA.

Animals↗
PubMed1992

Distribution of type I interleukin-1 receptor messenger RNA in testis: an in situ histochemical study in the mouse.

The cytokine interleukin-1 (IL-1) has been reported to inhibit the hypothalamic-pituitary-gonadal axis, both through actions in brain and at the gonadal level. Recently, high affinity binding sites for 125I-recombinant human IL-1 alpha have been identified in the mouse testis with characteristics similar to those of type I IL-1 receptors on T lymphocytes and fibroblasts. The present study employed in situ hybridization histochemistry with 35S-labeled antisense cRNA probes derived from a murine type I IL-1 receptor cDNA to identify type I IL-1 receptor mRNA in the mouse testis. An intense signal was observed over interstitial cells, and over the cytoplasm of the epithelium of epididymal ducts, most prominently in the head region. The signal over seminiferous tubules, and over sperm cells within tubules and epididymal ducts, was comparable to background. This distribution of type I IL-1 receptor mRNA was similar to that recently reported for 125(I)I-IL-1-alpha binding sites, and supports evidence implicating IL-1 as a direct regulator of gonadal function.

Animals↗
PubMed1992

Neuromedin B receptors retain functional expression when transfected into BALB 3T3 fibroblasts: analysis of binding, kinetics, stoichiometry, modulation by guanine nucleotide-binding proteins, and signal transduction and comparison with natively expressed receptors.

The receptor that interacts with the mammalian bombesin-related peptide neuromedin B (NMB) is ubiquitous in the gastrointestinal tract and central nervous system. However, little is known regarding its cellular mechanisms of action. This receptor has been recently cloned, sequenced, and stably transfected into BALB 3T3 fibroblasts, permitting detailed study of the pharmacology and coupled biological activities of this receptor. In the present study, we compare the ability of transfected receptors to alter cell function with that of receptors natively expressed in small numbers by the rat glioblastoma cell line C6. NMB inhibited binding of 125I-[D-Tyro]NMB with high affinity in transfected cells (Ki = 3.08 +/- 0.14 nM) and in C6 cells (Ki = 1.90 +/- 1.10 nM), whereas the bombesin-related agonists gastrin-releasing peptide (GRP) and [D-Phe6, D-Ala11, Leu14]bombesin(6-16) (GRP analogue) had 100- and 300-fold lower affinities, respectively, for NMB receptors in either cell type. For both cell systems, maximal binding was observed between 5 and 15 min at 22 degrees. Both cell types internalized NMB at similar rates, with > 70% of bound ligand being internalized by 60 min at 22 degrees. The nonhydrolyzable guanosine analogue guanosine 5'-(beta,gamma-imido)triphosphate was equipotent in causing a decrease in binding of 125I-[D-Tyro]NMB due to decreased receptor affinity in both cell types, without a change in receptor number, demonstrating that the NMB receptor remained coupled to a guanine nucleotide-binding protein in both native and transfected cells. In both cell systems, NMB increased inositol monophosphate, inositol bisphosphate, and inositol trisphosphate in a time-dependent fashion. Inositol phosphates were increased in a dose-dependent fashion, with similar half-maximal values being obtained for NMB in both cell types (transfected, 1.01 +/- 0.09 nM; C6, 2.09 +/- 0.15 nM) and for the GRP analogue (transfected, 1855 +/- 140 nM; C6, 2129 +/- 250 nM). NMB mobilized intracellular Ca2+ in both cell systems, and the dose-response curves were superimposible (EC50 for transfected, 0.10 +/- 0.08 nM; C6, 0.11 +/- 0.02 nM). These data demonstrate that activation of the receptor for NMB stimulates phospholipase C and increases intracellular Ca2+. These results also demonstrate that transfected and native NMB receptors behave similarly, suggesting that the transfected cell line will be useful in future studies investigating ligand-receptor interactions, as well as in molecular biological studies of the structure-function relationship of the receptor.

3T3 Cells↗
PubMed1992

In situ histochemical localization of type I interleukin-1 receptor messenger RNA in the central nervous system, pituitary, and adrenal gland of the mouse.

The cytokine interleukin-1 (IL-1) has a number of biologic activities, including pronounced effects on the nervous and neuroendocrine systems. In this study, in situ histochemical techniques were used to investigate the distribution of cells expressing type I IL-1 receptor mRNA in the CNS, pituitary, and adrenal gland of the mouse. Hybridization of 35S-labeled antisense cRNA probes derived from a murine T-cell IL-1 receptor cDNA revealed a distinct regional distribution of the type I IL-1 receptor, both in brain and in the pituitary gland. In the brain, an intense signal was observed over the granule cell layer of the dentate gyrus, over the entire midline raphe system, over the choroid plexus, and over endothelial cells of postcapillary venules throughout the neuraxis. A weak to moderate signal was observed over the pyramidal cell layer of the hilus and CA3 region of the hippocampus, over the anterodorsal thalamic nucleus, over Purkinje cells of the cerebellar cortex, and in scattered clusters over the external-most layer of the median eminence. In the pituitary gland, a dense and homogeneously distributed signal was observed over the entire anterior lobe. No autoradiographic signal above background was observed over the posterior and intermediate lobes of the pituitary, or over the adrenal gland. This study therefore provides evidence for discrete receptor substrates subserving the central effects of IL-1, thus supporting the notion that IL-1 acts as a neurotransmitter/neuromodulator in brain. It also supports studies suggesting that IL-1-mediated activation of the hypothalamic-pituitary-adrenal axis occurs primarily at the level of the brain and/or pituitary gland.

Adrenal Glands↗
PubMed1991

Two distinct bombesin receptor subtypes are expressed and functional in human lung carcinoma cells.

Bombesin-like peptides have been implicated as autocrine growth factors influencing the pathogenesis and progression of some human lung carcinoma cells. To determine the pharmacologic and structural properties of the bombesin receptors expressed in human lung carcinoma cells, cDNA clones encoding a human gastrin-releasing peptide receptor (GRP-R) and a pharmacologically distinct neuromedin-B preferring bombesin-receptor (NMB-R) were isolated from a human small cell lung carcinoma cell line (NCI-H345). After expression in Xenopus oocytes, a GRP-R-specific antagonist was effective in blocking responses elicited from the cloned GRP-R, but not the NMB-R. Both GRP-R and NMB-R mRNA expression was detected at varying levels in a panel of human lung cancer cell lines. These results indicate heterogeneity of bombesin receptor subtypes exists in human lung carcinoma cells and should be considered in the design of bombesin receptor antagonists intended to inhibit tumor cell growth.

Amino Acid Sequence↗
PubMed1991

Primary structure of alpha 2-macroglobulin receptor-associated protein. Human homologue of a Heymann nephritis antigen.

The alpha 2-macroglobulin (alpha 2M) receptor complex as purified by affinity chromatography contains three polypeptides: a 515-kDa heavy chain, an 85-kDa light chain, and a 39-kDa associated protein. Previous studies have established that the 515/85-kDa components are derived from a 600-kDa precursor whose complete sequence has been determined by cDNA cloning (Herz, J., Hamann, U., Rogne, S., Myklebost, O., Gassepohl, H., and Stanley, K. (1988) EMBO J. 7,4119-4127). We have now determined the primary structure of the human 39-kDa polypeptide, termed alpha 2M receptor-associated protein, by cDNA cloning. The deduced amino acid sequence contains a putative signal sequence that precedes the 323-residue mature protein. Comparative sequence analysis revealed that alpha 2M receptor-associated protein has 73% identity with a rat protein reported to be a pathogenic domain of Heymann nephritis antigen gp 330 and 77% identity to a mouse heparin-binding protein termed HBP-44. The high overall identity suggests that these molecules are interspecies homologues and indicates that the pathogenic domain, previously thought to be a portion of gp 330, is in fact a distinct protein. Further, the 120-residue carboxyl-terminal region of alpha 2M receptor-associated protein has 26% identity with a region of apolipoprotein E containing the low density lipoprotein receptor binding domain. Pulse-chase experiments revealed that the newly formed alpha 2M receptor-associated protein remains cell-associated, while surface labeling experiments followed by immunoprecipitation suggest that this protein is present on the cell surface forming a complex with the alpha 2M receptor heavy and light chains.

Amino Acid Sequence↗
PubMed1991

Distinguishing bombesin receptor subtypes using the oocyte assay.

Physiological responses to mammalian bombesin-like peptides were studied in Xenopus oocytes injected with mRNA isolated from Swiss 3T3 cells and rat esophagus in order to identify and characterize bombesin receptor subtypes. Both groups respond similarly to either gastrin releasing peptide or neuromedin B, but only the response to neuromedin B in oocytes expressing the esophagus mRNA is not blocked by a specific gastrin releasing peptide receptor antagonist, des-Met-[D-Phe6]Bn(6-13) ethyl ester. Complete desensitization of gastrin releasing peptide-evoked responses in oocytes expressing esophagus mRNA does not abolish neuromedin B-evoked responses. A single application of neuromedin B abolishes responses to subsequently applied gastrin releasing peptide in oocytes expressing esophagus, but not Swiss 3T3, mRNA. RNA blot hybridization studies using a Swiss 3T3 gastrin releasing peptide receptor cDNA probe show no detectable hybridization in esophagus mRNA samples. These data suggest that a gastrin releasing peptide receptor is expressed in the esophagus and that it is distinct from that expressed in Swiss 3T3 cells and may represent a third subtype of mammalian bombesin receptor.

Animals↗
PubMed1991

Molecular cloning of the bombesin/gastrin-releasing peptide receptor from Swiss 3T3 cells.

The mammalian bombesin-like peptides gastrin-releasing peptide (GRP) and neuromedin B regulate numerous and varied cell physiologic processes in various cell types and have also been implicated as autocrine growth factors influencing the pathogenesis and progression of human small cell lung carcinomas. We report here the molecular characterization of the bombesin/GRP receptor. Structural analysis of cDNA clones isolated from Swiss 3T3 murine embryonal fibroblasts shows that the GRP receptor is a member of the guanine nucleotide binding protein-coupled receptor superfamily with seven predicted hydrophobic transmembrane domains. In vitro transcripts from cloned cDNA templates encompassing the predicted protein coding domain, when injected into Xenopus oocytes, resulted in expression of functional GRP receptors. The predicted amino acid sequence of the open reading frame in cDNA clones matches the amino-terminal sequence as well as the sequence of four tryptic fragments isolated from the purified protein. Expression of the GRP receptor cDNA in model systems potentially provides a powerful assay for the development of subtype-specific receptor antagonists that may prove to be of therapeutic importance in human small cell lung carcinoma.

Amino Acid Sequence↗
PubMed1991

Localization of interleukin-1 receptor messenger RNA in murine hippocampus.

The cytokine interleukin-1 (IL-1) has numerous actions in brain, including pronounced neuroendocrine effects. Recent radioligand binding studies have identified high-affinity binding sites for 125I-recombinant human IL-1 alpha in the hippocampus with characteristics similar to those of IL-1 receptors in immune cells. The present study employed in situ hybridization histochemistry with 35S-labeled anti-sense cRNA probes derived from a full-length murine T-cell IL-1 receptor cDNA to identify cells producing IL-1 receptor mRNA in the murine hippocampus. An intense signal was observed over granule cells in the dentate gyrus. A weak to moderate signal was observed over the pyramidal cell layer of the hilus and CA3 region. Other aspects of the hippocampal formation, including the CA2 and CA1 regions, the subiculum, and the entorhinal area, displayed no signal above background. This distribution of IL-1 receptor mRNA was similar to that of 125I-IL-1 alpha binding sites and supports the growing body of evidence implicating IL-1 as a neurotransmitter/neuromodulator in brain.

Animals↗
PubMed1990

Expression of the atrial natriuretic factor gene in small cell lung cancer tumors and tumor cell lines.

Hyponatremia in patients with small cell lung cancer can be caused by tumor production of arginine vasopressin (AVP) and result in the syndrome of inappropriate antidiuretic hormone. In evaluating the expression of AVP mRNA from tumor and tumor cell line specimens from five patients with small cell lung cancer and hyponatremia (presumed to have the syndrome of inappropriate antidiuretic hormone), we found that the tumors and tumor cell lines from two of these five patients expressed AVP mRNA. The RNA samples from the three patients with undetectable AVP mRNA expressed abundant atrial natriuretic factor (ANF) mRNA. Analysis of specimens from three patients with small cell lung cancer and normal serum sodium levels revealed no detectable AVP mRNA expression, and samples from only one of these three patients' specimens expressed detectable ANF mRNA. The AVP and ANF peptide levels in lysate preparations of the tumor cell lines from four of these patients were tested by radioimmunoassay and confirmed the gene expression data. These studies demonstrate ectopic production of ANF mRNA in small cell lung cancer specimens from patients with this cancer and the syndrome of inappropriate antidiuretic hormone. These findings will be of particular interest if future studies demonstrate that ectopic ANF production can cause sodium abnormalities in patients with small cell lung cancer.

Aged↗
PubMed1990

N-myc mRNA forms an RNA-RNA duplex with endogenous antisense transcripts.

Nuclear runoff transcription studies revealed nearly equivalent sense and antisense transcription across exon 1 of the N-myc locus. Antisense primary transcription initiates at multiple sites in intron 1 and gives rise to stable polyadenylated and nonpolyadenylated transcripts. This pattern of antisense transcription, which is directed by RNA polymerase II, is independent of gene amplification and cell type. The nonpolyadenylated antisense transcripts have 5' ends which are complementary to the 5' ends of the N-myc sense mRNA. We determined, by using an RNase protection technique designed to detect in vivo duplexes, that most of the cytoplasmic nonpolyadenylated antisense RNA exists in an RNA-RNA duplex with approximately 5% of the sense N-myc mRNA. Duplex formation appeared to occur with only a subset of the multiple forms of the N-myc mRNA, with the precise transcriptional initiation site of the RNA playing a role in determining this selectivity. Cloning of each strand of the RNA-RNA duplex revealed that most duplexes included both exon 1 and intron 1 sequences, suggesting that duplex formation could modulate RNA processing by preserving a population of N-myc mRNA which retains intron 1.

Base Sequence↗
PubMed1990

Neuromedin B and gastrin-releasing peptide mRNAs are differentially distributed in the rat nervous system.

The bombesin-like peptides are a family of structurally related amidated peptide ligands that are known to have a variety of potent pharmacological actions on various cells, including neurons in the rat brain. Two mammalian representatives of the bombesin family of peptides have been identified, gastrin-releasing peptide (GRP) and neuromedin B (NMB). Previously, we cloned the rat preproGRP gene and determined the locations of neurons expressing this gene using in situ hybridization. In this study, we describe the structure and sequence of the rat preproNMB gene, and the first detailed cellular localization of preproNMB mRNA in rat brain using in situ hybridization. Nucleotide sequence analysis of cDNA and genomic clones reveals a 117 amino acid precursor whose overall structure is similar to that described for human preproNMB. Sequence similarity between the rat NMB and GRP genes is observed only over a limited 10 amino acid sequence encoding the carboxy termini of the GRP and NMB peptides, the region shown to be necessary and sufficient for high-affinity receptor binding. In situ hybridization studies performed with cRNA probes specific for NMB or GRP mRNA show that the distribution of cells expressing either mRNA in brain is very distinct. NMB mRNA is found most prominently in the olfactory bulb, dentate gyrus, and dorsal root ganglion. In contrast, the highest levels of GRP mRNA are observed in the forebrain (isocortex and hippocampal formation). This heterogeneity of mRNA distribution for these peptides suggests that these 2 structurally related peptides may have very distinct functions as neuropeptides in the rat nervous system.

Amino Acid Sequence↗
PubMed1989

A comparison of the metabolic fate of Fatty acids of different chain lengths in developing oilseeds.

To determine if medium and long chain fatty acids can be appropriately metabolized by species that normally produce 16 and 18 carbon fatty acids, homogenates of developing Cuphea wrightii, Carthamus tinctorius, and Crambe abyssinica seeds were incubated with radiolabeled lauric, palmitic, oleic, and erucic acids. In all three species, acyl-CoA synthetase showed broad substrate specificity in synthesis of acyl-coenzyme A (CoA) from any of the fatty acids presented. In Carthamus, two- to fivefold less of the foreign FAs, lauric, and erucic acid was incorporated into acyl-CoAs than palmitic and oleic acid. Lauric and erucic acid also supported less glycerolipid synthesis in Carthamus than palmitic and oleic acid, but the rate of acyl-CoA synthesis did not control rate of glycerolipid synthesis. In all species examined, medium and long chain fatty acids were incorporated predominantly into triacylglycerols and were almost excluded from phospholipid synthesis, whereas palmitic and oleic acid were found predominantly in polar lipids. However, the rate of esterification of unusual fatty acids to triacylglycerol is slow in species that do not normally synthesize these acyl substrates.

Journal Article↗