Human thyroid peroxidase: complete cDNA and protein sequence, chromosome mapping, and identification of two alternately spliced mRNAs.

Abstract

Two forms of human thyroid peroxidase cDNAs were isolated from a Xgtll cDNA library, prepared from Graves disease thyroid tissue mRNA, by use of oligonucleotides. The longest complete cDNA, designated phTPO-1, has 3048 nucleotides and an open reading frame consisting of 933 amino acids, which would encode a protein with a molecular weight of 103,026. Five potential asparagine-linked glycosylation sites are found in the deduced amino acid sequence. The second peroxidase cDNA, designated phTPO-2, is almost identical to phTPO-1 beginning 605 base pairs downstream except that it contains 1-base-pair difference and lacks 171 base pairs in the middle of the sequence. This results in a loss of 57 amino acids corresponding to a molecular weight of 6282. Interestingly, this 171-nucleotide sequence has GT and AG at its 5' and 3' boundaries, respectively, that are in good agreement with donor and acceptor splice site consensus sequences. Using specific oligonucleotide probes for the mRNAs derived from the cDNA sequences hTPO-1 and hTPO-2, we show that both are expressed in all thyroid tissues examined and the relative level of two mRNAs is different in each sample. These results suggest that two thyroid peroxidase proteins might be generated through alternate splicing of the same gene. By using somatic cell hybrid lines, the thyroid peroxidase gene was mapped to the short arm of human chromosome 2.

Prediction of domain organisation and secondary structure of thyroid peroxidase, a human autoantigen involved in destructive thyroiditis

“…The complete amino acid sequence of TPO has recently been deduced from cDNA cloning [8]. This revealed the presence of two different forms of mRNA Correspondence address: G.J.…”

“…This revealed the presence of two different forms of mRNA Correspondence address: G.J. Barton, Laboratory of Molecular Biophysics, The Rex Richards Building, South Parks Road, Oxford OX1 3QU, UK derived by alternative splicing of a single gene product [8]. The two forms of TPO, termed TPO-1 and TPO-2, have been fully sequenced and indicate that 57 residues are deleted in the shorter, TPO-2 form of the molecule [8,9].…”

“…Barton, Laboratory of Molecular Biophysics, The Rex Richards Building, South Parks Road, Oxford OX1 3QU, UK derived by alternative splicing of a single gene product [8]. The two forms of TPO, termed TPO-1 and TPO-2, have been fully sequenced and indicate that 57 residues are deleted in the shorter, TPO-2 form of the molecule [8,9]. The amino acid sequence of TPO exhibits a high degree of sequence similarity (42o70 identity) to myeloperoxidase (MPO) [10,11].…”

c-Kit Proto-oncogene Is More Likely to Lose Expression in Differentiated Thyroid Carcinoma Than Three Thyroid-specific Genes: Thyroid Peroxidase, Thyroglobulin, and Thyroid Stimulating Hormone Receptor.

“…The cDNA probes were labeled with x-32P-dCTP using a Takara Random Primer DNA Labeling Kit (Takara Co., Ltd., Otsu, Japan). The human TPO cDNA probe was a 2.4 kb Eco RI-Sac I fragment isolated by our group [19]. The human thyrogrobulin cDNA probe was a 0.96 kb Barn HI-Pst I fragment obtained from JCRB (Japanese Cancer Research Resources Bank) [20].…”

Localization of the Thyroid Peroxidase Autoantibody Immunodominant Region to a Junctional Region Containing Portions of the Domains Homologous to Complement Control Protein and Myeloperoxidase

“…TPO is a 933-amino acid residue molecule with a single membrane-spanning region (11)(12)(13). The major extracellular portion of the TPO molecule (amino acid residues 1-745) has high (ϳ42%) homology to myeloperoxidase (MPO), an intracellular enzyme whose three-dimensional structure has been determined (14).…”