scholarly journals An intron enhancer containing a 5' splice site sequence in the human calcitonin/calcitonin gene-related peptide gene.

1995 ◽  
Vol 15 (12) ◽  
pp. 7135-7142 ◽  
Author(s):  
H Lou ◽  
Y Yang ◽  
G J Cote ◽  
S M Berget ◽  
R F Gagel

Regulation of calcitonin (CT)/calcitonin gene-related peptide (CGRP) RNA processing involves the use of alternative 3' terminal exons. In most tissues and cell lines, the CT terminal exon is recognized. In an attempt to define regulatory sequences involved in the utilization of the CT-specific terminal exon, we performed deletion and mutation analyses of a mini-gene construct that contains the CT terminal exon and mimics the CT processing choice in vivo. These studies identified a 127-nucleotide intron enhancer located approximately 150 nucleotides downstream of the CT exon poly(A) cleavage site that is required for recognition of the exon. The enhancer contains an essential and conserved 5' splice site sequence. Mutation of the splice site resulted in diminished utilization of the CT-specific terminal exon and increased skipping of the CT exon in both the mini-gene and in the natural CT/CGRP gene. Other components of the intron enhancer modified utilization of the CT-specific terminal exon and were necessary to prevent utilization of the 5' splice site within the intron enhancer as an actual splice site directing cryptic splicing. Conservation of the intron enhancer in three mammalian species suggests an important role for this intron element in the regulation of CT/CGRP processing and an expanded role for intronic 5' splice site sequences in the regulation of RNA processing.

1998 ◽  
Vol 156 (3) ◽  
pp. 401-405 ◽  
Author(s):  
H Lou ◽  
RF Gagel

The calcitonin/calcitonin gene-related peptide (CT/CGRP) gene is one of the earliest studied examples of alternative RNA processing. The regulatory mechanisms controlling this event are poorly understood. We have identified and characterized an intron element residing in intron 4 of the human CT/CGRP gene. This intron element functions to enhance polyadenylation of an embedded alternative 3'-terminal exon within the CT/CGRP gene and is potentially involved in tissue-specific regulation of CT/CGRP RNA processing.


1989 ◽  
Vol 256 (2) ◽  
pp. E331-E335 ◽  
Author(s):  
T. Chiba ◽  
A. Yamaguchi ◽  
T. Yamatani ◽  
A. Nakamura ◽  
T. Morishita ◽  
...  

From this study, we predicted that the human calcitonin gene-related peptide (hCGRP) fragment hCGRP-(8-37) would be a selective antagonist for CGRP receptors but an agonist for calcitonin (CT) receptors. In rat liver plasma membrane, where CGRP receptors predominate and CT appears to act through these receptors, hCGRP-(8-37) dose dependently displaced 125I-[Tyr0]rat CGRP binding. However, hCGRP-(8-37) had no effect on adenylate cyclase activity in liver plasma membrane. Furthermore, hCGRP-(8-37) inhibited adenylate cyclase activation induced not only by hCGRP but also by hCT. On the other hand, in LLC-PK1 cells, where calcitonin receptors are abundant and CGRP appears to act via these receptors, the bindings of 125I-[Tyr0]rat CGRP and 125I-hCT were both inhibited by hCGRP-(8-37). In contrast to liver membranes, interaction of hCGRP-(8-37) with these receptors led to stimulation of adenosine 3',5'-cyclic monophosphate (cAMP) production in LLC-PK1 cells, and moreover, this fragment did not inhibit the increased production of cAMP induced not only by hCT but also by hCGRP. Thus hCGRP-(8-37) appears to be a useful tool for determining whether the action of CGRP as well as that of CT is mediated via specific CGRP receptors or CT receptors.


1991 ◽  
Vol 277 (1) ◽  
pp. 139-143 ◽  
Author(s):  
A Chantry ◽  
B Leighton ◽  
A J Day

This study examines whether the high degree of sequence identity between amylin and calcitonin-gene-related peptide (CGRP) is reflected in their cross-reactivity at the level of membrane receptor binding. Rat liver plasma membranes contain a specific saturable binding site for 125I-labelled human CGRP-1. Binding reached equilibrium within 30 min and was rapidly reversed by re-incubating membranes in the presence of 1 microM human CGRP. In addition, the presence of 50 mM- or 500 mM-NaCl lowered specific binding by 30% and 77% respectively. Scatchard analysis was consistent with a single high-affinity site with a dissociation constant (Kd) of 0.125 nM and binding capacity (Bmax.) of 580 fmol/mg of membrane protein. Specific binding of 125I-labelled human CGRP-1 to both liver and skeletal muscle membranes was inhibited by human CGRP-1 [IC50 (concn. causing half-maximal inhibition of binding) 0.1-0.3 nM], and rat amylin (IC50 10 nM), but not by human calcitonin. Covalent cross-linking of 125I-CGRP to its binding site in rat skeletal muscle and liver membranes resulted in labelling of a major species of about 70 kDa under reducing conditions and about 55 kDa under alkylating conditions, as visualized on SDS/PAGE. These radiolabelled species were absent in the presence of CGRP or amylin at 1 microM. These results are indicative of a common binding site for both CGRP and amylin in liver and skeletal muscle, and it is suggested that both peptides mediate their actions through the same effector system. The normal physiological importance and the relevance to the pathology of type 2 diabetes of these data are discussed.


2010 ◽  
Vol 16 (8) ◽  
pp. S73
Author(s):  
Asad Sheikh ◽  
James Vacek ◽  
Jeff Southard ◽  
Pamela Gayheart-Walsten ◽  
Ty Speece ◽  
...  

1990 ◽  
Vol 123 (6) ◽  
pp. 591-597 ◽  
Author(s):  
Bo Ahrén

Abstract. To study the influence of the pancreatic neuropeptides, galanin and calcitonin gene-related peptide, on insulin and glucagon secretion in man, synthetic porcine galanin (80 pmol·kg−1·min−1; N=6) or synthetic human calcitonin gen-related peptide (10 pmol·kg−1·min−1; N = 5) was infused intravenously in human volunteers. Following 5 min of infusion, arginine (5 g bolus + 10 mg·kg−1·min−1) was given. Galanin did not affect basal or arginine-stimulated insulin secretion judged from determinations of plasma insulin and C-peptide. Similarly, galanin did not affect arginine-stimulated glucagon secretion. Calcitonin gene-related peptide did not affect basal or arginine-stimulated insulin or glucagon secretion. However, calcitonin gene-related peptide slightly potentiated the arginine-induced hyperglycemia (p<0.01). Thus, in man, galanin has no influence on insulin or glucagon secretion when infused at 80 pmol·kg−1·min−1, whereas CGRP at 10 pmol·kg−1·min−1 induces slight hyperglycemia.


1986 ◽  
Vol 70 (4) ◽  
pp. 389-393 ◽  
Author(s):  
A. D. Struthers ◽  
M. J. Brown ◽  
D. W. R. Macdonald ◽  
J. L. Beacham ◽  
J. C. Stevenson ◽  
...  

1. In addition to calcitonin and katacalcin, it is now known that the human calcitonin gene encodes a novel peptide called calcitonin gene related peptide (CGRP). In experimental animals, CGRP produces vasodilatation and complex changes in plasma calcium. 2. We have now assessed its biological activity in man by infusing human CGRP (hCGRP) into six normal volunteers. hCGRP (545 pmol/min) caused the diastolic pressure to fall from 64 ± 5 to 55 ± 7mmHg (P < 0.05), the heart rate to increase from 61 ± 7 to 87 ± 5 beats/min (P < 0.05) and the skin temperature to increase from 33.7 ± 0.9 to 34.9 ± 0.5°C. Plasma noradrenaline increased from 481 ± 126 to 835 ± 65 pg/ml (P < 0.05) and plasma adrenaline from 57 ± 17 to 82 ± 12 pg/ml (P < 0.05). There were no significant changes in the albumin-corrected plasma calcium. 3. hCGRP is thus a potent endogenous vasodilator in man and is in fact more potent than any other known vasodilator. Together with the observations that CGRP circulates in normal subjects at relatively high concentration (approximately 25 pmol/l) and that CGRP is present in perivascular nerves, this study suggests a possible role for CGRP in controlling peripheral vascular tone in man.


Sign in / Sign up

Export Citation Format

Share Document