Biosynthesis and Release of Vasopressin and Neurophysin

Sachs, Hans; Fawcett, Peter; Takabatake, Yutaka; Portanova, Ronald

doi:10.1016/b978-0-12-571125-8.50013-2

Cited by 118 publications

(83 citation statements)

References 47 publications

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“…These mRNAs increase in amount with functional activity (Mohr et al 1991;Mohr and Richter 1992;Mohr and Richter 2003;Murphy et al 1989;Trembleau et al 1995;Trembleau et al 1994;Trembleau et al 1996). However, is well established that these mRNAs are not translated in the axons and terminals in the posterior pituitary to the precursor proteins and peptides (Brownstein et al 19 1980; Gainer et al 1977a;Sachs et al 1969). The synthetic pathway and post-translational processing for these precursor proteins to be converted into their peptide products requires a rough endoplasmic reticulum (RER) and a Golgi apparatus, organelles that are present in the neuronal cell bodies, but are absent from the pituitary axons and nerve endings (Brownstein et al 1980;Burbach et al 2001).…”

Section: Discussionmentioning

confidence: 99%

Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins

et al. 2016

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When isolated squid giant axons are incubated in radioactive amino acids, abundant newly synthesized proteins are found in the axoplasm. These proteins are translated in the adaxonal Schwann cells and subsequently transferred into the giant axon. The question as to whether any de novo protein synthesis occurs in the giant axon itself is difficult to resolve because the small contribution of the proteins possibly synthesized intra-axonally is not easily distinguished from the large amounts of the proteins being supplied from the Schwann cells. In this paper we reexamine this issue by studying the synthesis of endogenous neurofilament (NF) proteins in the axon. Our laboratory previously showed that NF mRNA and protein is present in the squid giant axon, but not in the surrounding adaxonal glia. Therefore, if the isolated squid axon could be shown to contain newly synthesized NF protein de novo, it could not arise from the adaxonal glia. The results of experiments in this paper show that abundant 3H-labeled NF protein is synthesized in the squid giant fiber lobe containing the giant axon's neuronal cell bodies, but despite the presence of NF mRNA in the giant axon, no labeled NF protein is detected in the giant axon. This lends support to the Glia-Axon Protein Transfer Hypothesis which posits that the squid giant axon obtains newly synthesized protein by Schwann cell transfer and not through intra-axonal protein synthesis, and further suggests that the NF mRNA in the axon is in a translationally repressed state.

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Section: Discussionmentioning

confidence: 99%

Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins

et al. 2016

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“…The oxytocin, vasopressin, and neurophysins are transported, in axons of the neurons that synthesize them, to the posterior pituitary via the median eminence. Sachs and his colleagues (4)(5)(6)(7)(8) have hypothesized that vasopressin and its neurophysin come from a common precursor protein that is synthesized in the hypothalamus by a ribosomal mechanism. We have already presented some evidence consistent with this hypothesis (9,10 sopressin and its associated neurophysin (11,12) and hence have diabetes insipidus-to determine which of the putative precursors, intermediates, and neurophysins are related to vasopressin and which to oxytocin.…”

mentioning

confidence: 99%

Neurophysin biosynthesis in normal rats and in rats with hereditary diabetes insipidus.

Brownstein¹,

Gainer²

1977

Proc. Natl. Acad. Sci. U.S.A.

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When [35S]cysteine was injected adjacent to the supraoptic nucleus (SON) in rats, it was rapidly incorporated into proteins in the SON. The [35S]cysteine-labeled proteins extracted from the SON were separated by isoelectric focusing on polyacrylamide gels. Twenty minutes after the injection of [I Scysteine, two major labeled peaks (pI = 5.4 and 6.1) were found in the SON of normal rats; Brattleboro rats had only one major labeled peak (pI = 5.4). One hour after the injection, four major radioactive peaks were found in the SON of normal animals (pI = 5.1,5.4,5.6, and 6.1). Animals with diabetes insipidus had only two major labeled proteins (pl = 5.1 and 5.4). Twenty-four hours after normal rats were injected with l35S-cysteine, all of the labeled peaks described above, except for the one with pI = 5. Neurons in the supraoptic nucleus (SON) and paraventricular nucleus synthesize two peptide hormones (oxytocin and vasopressin) as well as their "carrier" proteins (neurophysins) (1-3). The oxytocin, vasopressin, and neurophysins are transported, in axons of the neurons that synthesize them, to the posterior pituitary via the median eminence. Sachs and his colleagues (4-8) have hypothesized that vasopressin and its neurophysin come from a common precursor protein that is synthesized in the hypothalamus by a ribosomal mechanism. We have already presented some evidence consistent with this hypothesis (9, 10).We have found that, within 1 hr, [a3S]cysteine injected adjacent to the SON is incorporated into two proteins with molecular weights (Mr) of about 20,000 and pI of 5.4 and 6.1 (9, 10). It appears that, in time, these two proteins give rise to the two neurophysins (Mr 12,000). sopressin and its associated neurophysin (11, 12) and hence have diabetes insipidus-to determine which of the putative precursors, intermediates, and neurophysins are related to vasopressin and which to oxytocin. MATERIALS AND METHODS Animals and Operative Procedures. Female OsborneMendel (225-250 g) and Brattleboro (130-150 g) rats were used in these studies. Some of the normal Osborne-Mendel rats were given 2% (wt/vol) saline to drink for 1 week prior to use in order to stimulate vasopressin and neurophysin synthesis; others were given water ad lib as were the Brattleboro animals.The animals were anesthetized with ether, their heads were fixed in a stereotaxic device (50, nose down), and a flap of bone was removed from their skulls. The 30-gauge stainless steel needles were positioned 7 mm rostral to the interauricular line (6.8 mm for Brattleboro rats), and 2.5 mm on each side of the midline (2 mm for Brattleboro animals). The needles were lowered 8.6 mm (8.2 mm for Brattleboro animals) beneath the dural surface, and 1 ,ul of a solution containing 20,Ci of I35S]cysteine (50 Ci/mmol; New England Nuclear) in 0.9% NaCl and 10 mM dithiothreitol was injected through each needle over a 4-min period. After the injection, the needles were left in place for 10 min and then removed. At various times after the injections the rats were killed by...

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“…The hormones and their associated neurophysins are synthesized as common precursor in the perikarya of the supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus (2,3]. In [4], the sequence of a cDNA encoding the nonapeptide AVP and N, II was published.…”

Section: Introductionmentioning

confidence: 99%

Quantitative detection and biochemical characterization of high‐M_r forms of vasopressin in the rat hypothalamo—post‐hypophysial system

et al. 1982

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Biosynthesis and Release of Vasopressin and Neurophysin

Cited by 118 publications

References 47 publications

Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins

Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins

Neurophysin biosynthesis in normal rats and in rats with hereditary diabetes insipidus.

Quantitative detection and biochemical characterization of high‐M_r forms of vasopressin in the rat hypothalamo—post‐hypophysial system

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Biosynthesis and Release of Vasopressin and Neurophysin

Cited by 118 publications

References 47 publications

Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins

Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins

Neurophysin biosynthesis in normal rats and in rats with hereditary diabetes insipidus.

Quantitative detection and biochemical characterization of high‐Mr forms of vasopressin in the rat hypothalamo—post‐hypophysial system

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Quantitative detection and biochemical characterization of high‐M_r forms of vasopressin in the rat hypothalamo—post‐hypophysial system