Search results for "Intercellular transport"
showing 5 items of 5 documents
In Vivo RNA Labeling Using MS2
2014
The trafficking and asymmetric distribution of cytoplasmic RNA is a fundamental process during development and signaling across phyla. Plants support the intercellular trafficking of RNA molecules such as gene transcripts, small RNAs, and viral RNA genomes by targeting these RNA molecules to plasmodesmata (PD). Intercellular transport of RNA molecules through PD has fundamental implications in the cell-to-cell and systemic signaling during plant development and in the systemic spread of viral disease. Recent advances in time-lapse microscopy allow researchers to approach dynamic biological processes at the molecular level in living cells and tissues. These advances include the ability to la…
Cyclic adenosine monophosphate is a key component of regulatory T cell–mediated suppression
2007
Naturally occurring regulatory T cells (T reg cells) are a thymus-derived subset of T cells, which are crucial for the maintenance of peripheral tolerance by controlling potentially autoreactive T cells. However, the underlying molecular mechanisms of this strictly cell contact–dependent process are still elusive. Here we show that naturally occurring T reg cells harbor high levels of cyclic adenosine monophosphate (cAMP). This second messenger is known to be a potent inhibitor of proliferation and interleukin 2 synthesis in T cells. Upon coactivation with naturally occurring T reg cells the cAMP content of responder T cells is also strongly increased. Furthermore, we demonstrate that natur…
Deficiency of bile acid transport and synthesis in oval cells from carcinogen-fed rats.
1994
Freshly isolated oval cells, which we obtained from the livers of rats fed a choline-deficient/DL-ethioninesupplemented diet, did not transport bile acids. Compared with freshly isolated rat hepatocytes they took up only negligible amounts of [3H]taurocholate or [14C]cholate. The cells bound small amounts of radioactive bile acids. This portion of the total cell-associated radioactivity was enhanced on membrane permeabilization. In contrast to cultured liver parenchymal cells from untreated rats, no bile acid synthesis was detected in cultured oval cells. Cultured oval cells also lost the ability to conjugate exogenously added cholate (100 μmol/L) with taurine or glycine. However, when live…
Identification of a copper chaperone from tomato fruits infected with Botrytis cinerea by differential display
2003
Differential display was used to isolate tomato genes responding to fungal infection. Here we describe the isolation and characterization of a gene that is down-regulated in tomato fruits infected with the phytopathogen Botrytis cinerea. The cDNA identified encodes a protein that shares sequence similarity to the amino terminal region of CCH, a copper chaperone from Arabidopsis thaliana, that participates in intracellular copper homeostasis by delivering Cu to the secretory pathway. The fact that this newly characterized tomato gene, referred to as LeCCH (Lycopersicon esculentum copper chaperone), be differentially expressed after fungal infection, suggests an interesting relationship betwe…
Evidence for the plant-specific intercellular transport of the Arabidopsis copper chaperone CCH
2001
Summary Arabidopsis copper chaperone (CCH) belongs to a family of eukaryotic proteins that participates in intracellular copper homeostasis by delivering this metal to the secretory pathway. In this work we show that the CCH protein is mainly located along the vascular bundles of senescing leaves and petioles, as shown by tissue prints and immunohistochemical detection. CCH protein also accumulates in stem sieve elements and is collected in phloem exudates. Accordingly, Arabidopsis CCH is the only member of the metallochaperone family described to function intercellularly to date. Moreover, the CCH protein remains stable when plants are subjected to excess copper that causes a rapid and spe…