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Biosynthesis and posttranslational processing of the neurotensin/neuromedin N precursor in the rat medullary thyroid carcinoma 6-23 cell line. Effect of dexamethasone.

Authors: De Nadai, F  Rovere, C  Bidard, JN  Laur, J  Martinez, J  Cuber, JC  Kitabgi, P 
Citation: de Nadai F, etal., Endocrinology. 1993 Apr;132(4):1614-20.
Pubmed: (View Article at PubMed) PMID:8462460
DOI: Full-text: DOI:10.1210/endo.132.4.8462460

Neurotensin (NT) and Neuromedin N (NN) are two biologically active peptides present in one copy each in the C-terminal region of a 169-residue precursor. Four basic Lys-Arg doublets occur within the precursor and represent putative processing sites. We investigated the effects of dexamethasone on the biosynthesis and the posttranslational processing of the NT/NN precursor in the rat medullary thyroid carcinoma 6-23 cell line (rMTC 6-23). Western blot analysis and RIA coupled to HPLC and arginine-directed tryptic cleavage of precursor forms were performed with antisera specific for precursor sequences adjacent to the four basic doublets. These studies revealed that rMTC 6-23 cells synthesized the NT/NN precursor in response to dexamethasone and had the capability to process this precursor at the three Lys-Arg doublets that flank and separate NT and NN, thus yielding authentic NT, NN, and several larger products. The most N-terminal Lys-Arg doublet was not processed in this system. Dexamethasone increased in a concentration- and time-dependent manner the levels of all the NT/NN precursor-derived products. This increase did not affect the relative proportion of the different products. We also showed by Northern blot analysis that both the 1.1-kilobase and 1.5-kilobase NT/NN precursor messenger RNAs were present in the rMTC 6-23 cell line and that the time course and dose response of dexamethasone-induced messenger RNA synthesis were in good agreement with those observed for dexamethasone-induced increase in processing products. The rMTC 6-23 cell line represents a good model to elucidate the steps involved in the posttranslational processing of the NT/NN precursor.


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CRRD Object Information
CRRD ID: 9727457
Created: 2015-02-17
Species: All species
Last Modified: 2015-02-17
Status: ACTIVE


RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.