Copia RNA levels are elevated in dunce mutants and modulated by cAMP

Yun, Yungdae; Davis, Ronald L.

doi:10.1093/nar/17.20.8313

Cited by 11 publications

(3 citation statements)

References 41 publications

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“…Cyclic AMP (CAMP) Several Drosophila mutants with defective learning and short-term memory have alterations in adenylate cyclase, CAMP phosphodiesterase, or related enzymes (Dudai, 19881, with concomitant alterations in mRNA levels (Yun and Davis, 1989) and protein phosphorylation (Buxbaum and Dudai, 1989). Although certainly not an adequate model for autism, study of such mutants may provide background for the neurochemical investigation of cognitive development in autism and other developmental disorders.…”

Section: Second-messenger Systemsmentioning

confidence: 99%

Autism: Review of neurochemical investigation

Cook

1990

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171

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The neurochemistry of autism, the most well-validated childhood neuropsychiatric disorder, has been studied extensively over the past three decades. Autism is of interest neurochemically because it represents a relatively homogeneous disorder with a triad of social, communicative, and intellectual developmental disturbance. Because a sufficient animal model has been lacking and relatively few diagnosed people with autism have died, most investigation has been of peripheral fluids and tissues. The most consistent finding has been that over 25% of autistic children and adolescents are hyperserotonemic. However, after 29 years of investigation, the mechanism of hyperserotonemia has not been determined. Hyperserotonemia has been found to be familial. Elevated plasma norepinephrine has also been a replicated finding. Cerebrospinal fluid (CSF) opiate activity has been found to be elevated in two studies. Plasma cyclic adenosine monophosphate (cAMP) has been found to be elevated in autistic children. A high rate of nonsuppression after dexamethasone and blunted or delayed growth hormone response to L-dopa have been found. Abnormal cell-mediated immunity has been replicated consistently in autism. Although several pharmacological trials have been conducted and shown promise in initial open trials, only "typical" antipsychotic drugs have shown replicable chronic ameliorating effects in double-blind trials. However, chronic neurotoxicity (tardive dyskinesia) has also been revealed. Findings of morphological changes in the cerebellum have been replicated. Findings in need of replication include diminished platelet function, increased baseline CSF homovanillic acid, decreased nerve cell adhesion molecule serum fragment, blunted prolactin response to fenfluramine, amelioration of symptoms by naltrexone and bromocriptine, reduced electroretinographic (ERG) b-wave amplitude, and morphological changes in the hippocampus, amygdala, and septal nuclei. In addition to refining and replicating past findings, future directions that may be fruitful include investigation of neurochemical aspects of platelet function, of interactions between monoaminergic systems, of phosphatidylinositides, and of pharmacological response to "atypical" antipsychotic agents and relatively selective serotonin receptor subtype agonists or antagonists.

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Section: Second-messenger Systemsmentioning

confidence: 99%

Autism: Review of neurochemical investigation

Cook

1990

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171

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“…Transcription of retrotransposons is active during the normal life cycle of these organisms. Many environmental or endogenous factors can also modulate transcription, for example heat shock (Strand and McDonald, 1985), UV light (Bradshaw and McEntee, 1989), steroid hormones (Ziarczyk et al, 1989) and cAMP (Yun and Davis, 1989). It has been shown that transcription of Drosophila retrotransposons is both developmentally regulated and activated in cell culture (for review, see Echalier, 1989).…”

Section: Introductionmentioning

confidence: 99%

Activation of tobacco retrotransposons during tissue culture.

1993

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Sequences of at least three new families of retrotransposons (Tto1‐Tto3) were amplified by PCR from cDNA prepared from protoplasts of an established tobacco cell line, based on the fact that certain amino acids are highly conserved in the reverse transcriptases encoded by retrotransposons. Structural analysis indicates that Tto1 is 5.5 kb long and has features typical of retrotransposons. Transcription of Tto1 starting in the long terminal repeat was active only in cultured cells. Protoplast formation enhanced the transcription. The copy number of Tto1 increased 10‐fold in established cell lines; it also increased in plants regenerated from tissue cultures and in transgenic plants. These results indicate that Tto1 is activated during tissue culture. This is the first demonstration of activation of a plant retrotransposon by tissue culture. The copy number of Tto2 and a previously isolated transposon, Tnt1, also increased in established cell lines, indicating that these two retrotransposons may also be activated by tissue culture. These three retrotransposons are cryptic in normally propagated plants: no difference in the copy number was observed between individuals of the same cultivars or even between different cultivars.

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“…Most well-studied retrotransposons are transcribed at relatively high levels (Flavell et al, 1980;Schwartz et al, 1982;Boeke, 1989). Their transcription is modulated by a number of environmental and physiological factors, such as steroid hormones (Ziarczyk et al, 1989), stress, including heat shock (Strand and McDonald, 1985), cAMP level (Yun and Davis, 1989), and DNA damaging agents like UV light (Bradshaw and McEntee, 1989). Furthermore, RNAs of a number of Drosophila retrotransposons are also developmentally regulated (Schwartz et al, 1982;Parkhurst and Corces, 1987), and Ty transcription is under mating-type 1911 control (Boeke, 1989).…”

Section: Introductionmentioning

confidence: 99%

Specific expression of the tobacco Tnt1 retrotransposon in protoplasts.

et al. 1991

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The Tnt1 transposable element of tobacco belongs to the retrotransposon family and shares the structural features of viral retroelements including two long terminal repeats (LTRs) which are known to contain promoter regions. We show that two Tnt1 RNAs of 5.2 and 6.5 kb can be found. The 5.2 kb RNA matches with the size of the Tnt1 elements so far isolated (5.3 kb), whilst the evidence suggests that the 6.5 kb RNA could be a chimaeric RNA initiated in a gene in which Tnt1 has inserted. The Tnt1 5.2 kb RNA starts in the LTR, and the LTR can promote the expression of a translational LTR‐beta‐glucuronidase (GUS) fusion at a high level in transient expression assays. The Tnt1 5.2 kb RNA and the LTR‐GUS fusion of transgenic tobacco plants are specifically expressed in leaf‐derived protoplasts whereas they are not expressed in leaf tissue. The 5.2 kb RNA is also transcribed at low levels in roots. This RNA is induced after 2 h of maceration in the protoplast isolation medium, and its level declines rapidly after protoplast isolation. The induction requires only the presence of cell wall hydrolases, and is independent of wounding and plasmolysis. The induction of Tnt1 expression is not mediated by typical oligosaccharide elicitors released from the cell wall known to mediate defense gene responses. Tnt1 transcription features provide a first example of tissue culture‐induced mutagenesis in plants and a molecular basis for some of the somaclonal variation events.

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Copia RNA levels are elevated in dunce mutants and modulated by cAMP

Cited by 11 publications

References 41 publications

Autism: Review of neurochemical investigation

Autism: Review of neurochemical investigation

Activation of tobacco retrotransposons during tissue culture.

Specific expression of the tobacco Tnt1 retrotransposon in protoplasts.

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