Carbon dioxide reversibly abolishes ionic communication between cells of early amphibian embryo

Turin, Luca; Warner, Alan

doi:10.1038/270056a0

Cited by 309 publications

(124 citation statements)

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“…The phosphorylation is thought to accelerate the breakdown of the compound to inositol trisphosphate, which releases calcium ions from internal stores, and diacylglycerol, which activates protein kinase C (10). Furthermore, since PMA, the potent tumor promoter, is known not only to block intercellular communication (15,16) and to alter gap junction function (34,35) (36,37). It is possible that the src gene product may increase inositol trisphosphate and release free calcium, which, in turn, may reduce the cyclic AMP level and gap-junctional communication (38).…”

Section: Discussionmentioning

confidence: 99%

Potential role of the src gene product in inhibition of gap-junctional communication in NIH/3T3 cells.

Chang

Trosko

Kung

et al. 1985

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

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The effects of the src gene on the activity of protein kinase C and intercellular communication have been studied in transformed NIH/3T3 clones isolated from soft agar following transfection with the plasmid carrying the v-src gene (psrc-l1). Six transformed clones that were studied contained newly incorporated v-src genes in the genome, had an increased amount of pp6src, and showed enhanced activities of protein kinase C. Intercellular communication, studied by observing with autoradiography the transfer of [3H]uridine nucleotide from prelabeled donor cells to recipient cells in contact, was found to be reduced in transformed clones as compared to parental NIH/3T3 cells. Treatment with phorbol 12-myristate 13-acetate was also found to increase protein kinase C activity and to reduce intercellular communication in normal NIH/3T3 cells. These results suggest that the v-src gene product, in a manner similar to some of the powerful tumor promoters, may directly or indirectly affect cell-cell communication.The identification of the role of many genes involved in the complex multistep carcinogenic process has begun with the development of techniques to detect oncogenes in vitro (1). The recent demonstrations that some oncogenes code for a growth factor (2-4), growth factor receptor (5), and several tyrosine-directed protein kinases (6) suggest that many of these oncogenes have growth-promoting effects. More recently, the discovery that some oncogene products can phosphorylate phosphatidylinositol (7,8) MATERIALS AND METHODSIsolation of src Gene-Transformed NIH/3T3 Clones. NIH/3T3 cells, used as DNA recipients, were grown in Dulbecco's modified minimal essential medium supplemented with 10% fetal calf serum at 37°C in water-jacketed incubators that provide 5% CO2 in air and humidity. The donor DNA carrying the v-src gene is a plasmid (psrc"l) provided to us by G. Cooper (Harvard Medical School). This plasmid contains an intact Rous sarcoma virus v-src gene with two long terminal repeat promoters positioned both upstream and downstream from the gene, in such a way that the v-src messages can be effectively expressed (see Fig. 10. The transfection experiments followed the procedure described by Wigler et al. (24). The total DNA per plate was 20 ,ug which includes plasmid DNA (0-10 ,ug per plate) and salmon DNA (10-20 ,tg per plate). After 5 hr of incubation with calcium phosphate/DNA precipitate, the medium was removed and the attached cells were treated with 20% glycerol in phosphate-buffered saline (P1/NaCl) for 1 min.After rinsing with Pi/NaCl, fresh medium was added to each plate. The cells were cultured for 2 weeks with a change of medium every 3 days before the plates were overlayed with 0.28% agarose. After an additional week, colonies that developed into the soft agar were isolated for further studies.Iletermination of the Presence of Transfected src Gene in NIH/3T3 Clones. DNA of NIH/3T3 clones was isolated by the procedure of Maniatis et al. (25). Forty micrograms of DNA from each cell line was dig...

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Section: Discussionmentioning

confidence: 99%

Potential role of the src gene product in inhibition of gap-junctional communication in NIH/3T3 cells.

Chang

Trosko

Kung

et al. 1985

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

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“…This seems unlikely in view of the large body of evidence implicating one or both ions in most of the well studied instances of intercellular coupling (Rose & Loewenstein, 1976;Deleze & Loewenstein, 1976;Turin & Warner, 1977;Bennett, Brown, Harris & Spray, 1978).…”

Section: Effects Of Drugs On Perfumed Axonsmentioning

confidence: 99%

Electrotonic coupling in internally perfused crayfish segmented axons.

Johnston¹,

Ramón²

1981

The Journal of Physiology

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SUMMARYWe have developed a technique for cannulation and internal perfusion of crayfish segmented lateral axons. Experiments on perfused and non-perfused axons lead to the following conclusions:1. Internally perfused segmented axons behave very similarly to non-perfused axons.2. The axial electrical resistance of the junctional region is almost as low as a comparable segment of axon.3. Neither intracellular Ca2+ nor H+ is effective in disrupting the intercellular communication pathway in perfused axons.On the basis of these findings we have formulated a hypothesis for cellular control of intercellular coupling based on the existence of a soluble intermediate for Ca2+ or H+-induced uncoupling. This hypothesis is consistent with data from both internally perfused and non-perfused axons.

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“…On the shortest time scale, it is known that gap-junction channels are gated by voltage and can display multiple voltage-dependent conductance states (Turin and Warner 1977;Spray et al 1979;Neyton and Trautmann 1985;Chen and DeHaan 1992;Bukauskas and Weingart 1993). Voltage-gating is a common property of connexins, although they show substantive differences in their sensitivities.…”

Section: Rapid Regulationmentioning

confidence: 99%