Comparison of brain ribonucleases of rabbit, guinea pig, rat, mouse and gerbil

Schulz‐Harder, Bernd; Keyserlingk, D Graf von

doi:10.1007/bf00570329

Cited by 12 publications

(6 citation statements)

References 27 publications

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“…First, mRNAs could have differential half-lives in the axon. However, RNase levels in the axon appear very low (Schulz-Harder and von Keyserlingk, 1988), and it seems unlikely that differential degradation is a major determi- nant in the establishment of the composition of the axonal RNA population. Second, axonal mRNAs may be selectively transported from the cell soma, and evidence for the axonal transport of RNA in the squid giant fiber system has been reported (Cutillo et al, 1983).…”

Section: Discussionmentioning

confidence: 99%

Differential Compartmentalization of mRNAs in Squid Giant Axon

Chun

Gioio

Crispino

et al. 1996

Journal of Neurochemistry

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Previously, we reported that the squid giant axon contains a heterogeneous population of mRNAs that includes /3-actin, /3-tubulin, kinesin, neurofilament proteins, and enolase. To define the absolute levels and relative distribution of these mRNAs, we have used competitive reverse transcription-PCR to quantify the levels of five mRNAs present in the giant axon and giant fiber lobe (GFL), the location of the parental cell sorna. In the GFL, the number of transcripts for these mRNAs varied over a fourfold range, with~3-tubulin being the most abundant mRNA species (1.25 x i0 9 molecules per GFL). Based on transcript number, the rank order of mRNA levels in the GFL was~3-tubulin>~3-actin> kinesin > enolase > microtubule-associated protein (MAP) Hi. In contrast, kinesin mRNA was most abundant in the axon (4.1 X i0~'molecules per axon) with individual mRNA levels varying 15-fold. The rank order of mRNA levels in the axon was kinesin >~3-tubulin > MAP Hi > /3-actin > enolase. The relative abundance of the mRNA species in the axon did not correlate with the size of the transcript, nor was it directly related to their corresponding levels in the GFL. Taken together, these findings confirm that significant amounts of mRNA are present in the giant axon and suggest that specific mRNAs are differentially transported into the axonal domain. Key Words: Axonal mRNAs-Giant axon-Squid-Quantitative PCR.

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Section: Discussionmentioning

confidence: 99%

Differential Compartmentalization of mRNAs in Squid Giant Axon

Chun

Gioio

Crispino

et al. 1996

Journal of Neurochemistry

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“…The capacity to transport RNA from the perikaryon could be an important auxiliary mechanism for control of the synthetic activity of peptidergic neurons. Neurons are known to contain virtually no RNase activity (25,26). As peptidergic neurons can regulate their gene expression rate rapidly, intracellular segregation to the nonribosomal cytoplasm of the axon could provide an alternative to RNA degradation, as a means to reduce cytoplasmic mRNA levels.…”

Section: Discussionmentioning

confidence: 99%

mRNA coding for oxytocin is present in axons of the hypothalamo-neurohypophysial tract.

Jirikowski

Sanna

Bloom

1990

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

138

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Neuronal mRNA is thought to be restricted to perikaryal and dendritic compartments containing rough endoplasmic reticulum. We have used both in situ hybridization and DNA polymerase chain reaction methods to determine the precise intracellular distribution of oxytocin mRNA. Using light-and electron-microscopic detection of in situ hybridization with 5'-bromo-2'-deoxyuridine-labeled oligonucleotide probes, we found oxytocin mRNA in axons and Herring bodies in the lateral and ventral hypothalamus, the median eminence, and the posterior lobe of the pituitary in postpartum lactating rats. Southern blot analysis of the amplification products confirmed the presence of oxytocin mRNA in all three tissue samples. The present findings indicate that oxytocin mRNA can be transported axonally. Such transport could reflect an adventitious compartmentalization or a functional storage in Herring bodies for subsequent secretion. In the mammalian brain, specific intradendritic mRNAs are seen consistently (1,8,9). On the other hand, Guitteny and Bloch (10), using autoradiographic detection of vasopressin mRNA hybridization by both light and electron microscopy, reported that hybridization was restricted to perinuclear cytoplasm. Nevertheless, the micrographs presented in this study do not exclude the possibility that vasopressin mRNA is present in more distal neuronal processes. McCabe et al. (11) reported the presence of vasopressin mRNA in extracts of the posterior lobe by using solution hybridization. Although they did not directly determine the cellular origin of this mRNA, they suggested that it might arise from pituicytes (11), the major cell type in the posterior pituitary other than the vascular elements.We recently developed an immunocytochemical method for in situ hybridization with BrdUrd-labeled oligonucleotide probes (12). This sensitive nonradioactive method also provides resolution of hybridization sites by electron microscopy. In a recent light microscopy study, we found that oxytocin mRNA hybridization was present in neuronal processes at some distance from neuronal perikarya (13). Therefore, we initiated these studies to apply this method to an evaluation of possible intraaxonal localization of the mRNA for oxytocin in the posterior pituitary. The neurohypophysial magnocellular system is ideal for analysis ofthe intraneuronal compartmentalization of neuropeptide mRNAs as its cell bodies are concentrated within the hypothalamus, while the axons of these neurons are concentrated in neuron-free sites in the median eminence and neurophypophysis. Early lactating animals were chosen for these experiments to take advantage of their high rates of oxytocin synthesis (14) accompanied by high levels of oxytocin mRNA (15). Our results indicate that in this physiological state, the oxytocin mRNA can indeed be detected in the axons of oxytocincontaining neurons in the median eminence and the posterior pituitary by both light microscopy and ultrastructural in situ hybridization as well as in RNA samples from the poste...

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“…However, further analyses are required to test this hypothesis in distantly related ruminant species. According to our results, the human gene encoding the pancreatic RNAase is transcribed in brain, pancreas, and maremary glands (Sasso et al manuscript in preparation) and, in addition, alkaline ribonuclease activities, sensitive to the protein inhibitor, have been detected in the CNS of many different mammalian species (Shulz-Harder and Graf v. Keyserlingk 1988), suggesting a role in brain physiology; furthermore, the human pancreatic ribonuclease has been also isolated from kidney, milk, and seminal plasma (Beintema et al 1988). The presence of ribonuclease activities in a variety of tissues is therefore evolutionarily conserved, pointing to an important function of these enzymes in many different organs.…”

Section: T~g C G G T a A A C C G T~ G (~% L~t C G A T G C T T C A G Tmentioning

confidence: 99%

Molecular evolution of genes encoding ribonucleases in ruminant species

Confalone¹,

Beintema

Sasso

et al. 1995

J Mol Evol

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Phylogenetic analysis, based on the primary structures of mammalian pancreatic-type ribonucleases, indicated that gene duplication events, which occurred during the evolution of ancestral ruminants, gave rise to the three paralogous enzymes present in the bovine species. Herein we report data that demonstrate the existence of the orthologues of the bovine pancreatic, seminal, and cerebral ribonucleases coding sequences in the genomes of giraffe and sheep. The "seminal" sequence is a pseudogene in both species. We also report an analysis of the transcriptional expression of ribonuclease genes in sheep tissues. The data presented support a model for positive selection acting on the molecular evolution of ruminant ribonuclease genes.

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Comparison of brain ribonucleases of rabbit, guinea pig, rat, mouse and gerbil

Cited by 12 publications

References 27 publications

Differential Compartmentalization of mRNAs in Squid Giant Axon

Differential Compartmentalization of mRNAs in Squid Giant Axon

mRNA coding for oxytocin is present in axons of the hypothalamo-neurohypophysial tract.

Molecular evolution of genes encoding ribonucleases in ruminant species

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