An isoform of the human calcitonin receptor is expressed in TT cells and in medullary carcinoma of the thyroid

Abstract

We amplified, using the polymerase chain reaction and calcitonin receptor (CTR) specific primers, RNA extracted from medullary thyroid carcinoma (MTC) and the derived TT cell line. Both secrete large amounts of calcitonin. Electrophoresis of amplification products revealed, in both cases, an ethidium bromide‐stained band that hybridized to a CTR probe. Sequencing the band amplified from TT cells revealed an open reading frame identical to the sequence of H‐CTR but lacking 16 amino acids in the first intracellular loop. This demonstrates the existence of an mRNA coding for a subtype of H‐CTR which is expressed in TT cells and MTC.

Exogenous Calcitonin Suppresses Growth Fraction of Thyroid C Cells

“…It is reasonably certain that CT acts directly on C cells through CTR and causes this suppression of C cell proliferation because CTR mRNA has been expressed in human medullary thyroid carcinoma tissues and the medullary thyroid carcinoma cell line, TT cell [7][8][9]. Izumi et al have showed that osteoclasts on the bone surface express CTR by immunohistochemistry [12].…”

Molecular characterization of two novel isoforms of the human calcitonin receptor

“…2 and 4). They differed by the presence or absence of a 48-bp insert that is characteristic of two previously known H-CTR isoforms, H-CTR1 and H-CTR2 (Frendo et al, 1994;Kuestner et al, 1994;Gorn et al, 1995). Electrophoresis gel analysis suggested that a smaller amount of DNA contained both 48-and 50-bp inserts (Fig.…”

“…Numbers correspond to nucleotide position numbered from the 3V-in-frame ATG initiation site according to the first reported sequence (Gorn et al, 1992). 522-569 indicates limit positions of the 48-bp insert (not to scale) that is specific to the already known isoforms, H-CTR1 and H-CTR2 (Frendo et al, 1994;Gorn et al, 1995;Kuestner et al, 1994). Primers used for amplifications are shown as arrows (not to scale).…”

“…The cloned cDNA contains two translational initiation sites and therefore probably encodes a putative peptide of either 508 or 490 amino acids (aa). Three H-CTR isoforms were further characterized in terms of structure and function (Frendo et al, 1994;Kuestner et al, 1994;Albrandt et al, 1995;Gorn et al, 1995;. They are translated from alternatively spliced mRNA.…”

The <i>Alu</i>I Calcitonin Receptor Gene Polymorphism (TT) Is Associated with Low Bone Mineral Density and Susceptibility to Osteoporosis in Postmenopausal Women

“…The calcitonin receptor (CTR) is one of the families of transmembrane receptor proteins and has recently been sequenced and cloned in several mammalian species [7][8][9]. Three isoforms of the mRNA of human CTR, as a result of alternative splicing, have been described [10][11][12][13][14].…”