The complete sequence of human preprocalcitonin

Abstract

DNA complementary to mRNA extracted from the thyroid glands of patients suffering from medullary carcinoma of the thyroid (MCT), a calcitonin‐producing tumour, was inserted in the Pst site of pBR 322 by G‐C tailing. The recombinant plasmids were used to transform Escherichia coli DP 50. Ampicillin‐resistant clones were screened using a 32P‐labelled cDNA to mRNA extracted from a case of MCT particularly rich in calcitonin (CT) mRNA. Positive clones were subsequently rescreened using a 32P poly(T) probe. Eighty clones were thus purified, and the inserts obtained by digestion with PstI were subjected to positive hybridization selection with subsequent translation in vitro. An insert stimulating synthesis of the protein and containing restriction sites compatible with the previously published complete sequence of calcitonin mRNA from rat was sequenced. This cDNA insert contained the entire coding region of 426 bp, 70 bp at the 5′‐end, and 295 bp upstream from the poly(A) tail. The complete amino acid sequence of human preprocalcitonin could thus be deduced.

The sequence specificity of homeodomain-DNA interaction

“…To create the fusions to the calcitonin (CT) gene (construct C and D in Figure 1), a BgIII-BsmI (BsmI site blunted with mung bean nuclease) fragment encoding part of preprocalcitonin (Le Moullec et al, 1984) was cloned into pUC8 opened at the AccI (blunt-ended with mung bean nuclease) and BamHI sites. In the resulting construct, pLac.Ct, a calcitonin-containing peptide is expressed under the control of the lac promoter.…”

Preprocalcitonin signal peptide generates a cytotoxic T lymphocyte-defined tumor epitope processed by a proteasome-independent pathway

“…33). It is then immediately cleaved by SP (22) at the Ala 25 -Ala 26 site (19). ppCT 16 -25 peptide is at the C terminus of the leader sequence.…”

“…It contains one of the consensus HLA-A2 peptide-binding motifs, Leu, Ile, or Met in position 2, but fails to contain the peptide-binding motif, Leu or Val in position 10, and has therefore a moderate ability to bind to HLA-A2 (data not shown). This peptide corresponds exactly to the C-terminal part of the ppCT signal peptide (19).…”

“…Because the C terminus of antigenic peptide VLLQAGSLHA corresponded to the C terminus of the ppCT signal sequence (19), it was expected to be generated by type I SP, which cuts off signal peptides from secretory proteins on the luminal side of the ER membrane (22). SP involvement was tested by using the serine protease inhibitor dichloroisocoumarin (DCI) (23).…”

Procalcitonin in sepsis and bacterial infections

“…PCT is a 116 amino acid long peptide having a molecular weight of 13 KDa. 6 As the name suggests, it is a precursor of calcitonin, produced by the C-cells of thyroid under the control of the calcitonin gene related peptide 1 (CALC-1) gene. 7 Normally, the expression of the gene is found in the neuroendocrine cells of the thyroid and the lung.…”