Fine-needle aspiration biopsy-RT-PCR expression analysis of prothymosin alpha and parathymosin in thyroid: novel proliferation markers?

Fine-needle aspiration biopsy-based cytology has become an established and reliable diagnostic preoperative test in the evaluation of thyroid nodules. Despite the high specificity and sensitivity of the method, results might be doubtful in a significant number of cases. Genetic analysis of the aspirates by RT-PCR may contribute, in parallel to the cytology report, to a more precise diagnosis.

Surfing on prothymosin alpha proliferation and anti-apoptotic properties.

Prothymosin alpha is an extremely abundant nuclear oncoprotein-transcription factor essential for cell cycle progression and proliferation that has been recently suggested as an anti- apoptotic factor. Similarly to other oncoproteins, prothymosin alpha is overexpressed in a variety of cancer tissues and cell lines. The present review highlights on the proliferation and anti-apoptotic properties of prothymosin alpha and its possible role in cancer development.

Transcription factor-mediated proliferation and apoptosis in benign and malignant thyroid lesions.

Transcription factors play an essential role in regulating both cell proliferation and programmed cell death. Proliferation and apoptosis-related transcription factor immunoexpression patterns were concomitantly investigated in tissue sections of normal thyroid, goiters, follicular adenomas and well-differentiated papillary and follicular carcinomas using antibodies against prothymosin alpha, E2F-1, p53, Bcl2, and Bax proteins. Proliferation and apoptotic indices were determined by Ki-67 immunoreactivity and the terminal deoxynucleotidyl transferase-mediated deoxy uridine triphosphate nick-end labeling technique, respectively.

Prothymosin alpha is localized in mitotic spindle during mitosis.

Prothymosin a is a small, acidic, ubiquitous protein, thought to play a role in cell proliferation, carcinogenesis and apoptosis. We have reported earlier that in the interphase nucleus prothymosin a exhibits a punctuated nuclear distribution associated with transcription sites. Moreover, the protein was found to localize in 1-6 subnuclear domains where PML and CstF64 proteins were also identified.

Interferon induces the interaction of prothymosin-alpha with STAT3 and results in the nuclear translocation of the complex.

Interferons (IFNs) play critical roles in host defense by modulating the expression of various genes via tyrosine phosphorylation of STAT transcription factors. Many cytokines including IFNs induce tyrosine phosphorylation of the STAT3 transcription factor, which regulates acute phase gene expression. Using the yeast two-hybrid interaction trap, in which a tyrosine kinase is introduced into the yeast to allow tyrosine phosphorylation of bait proteins, prothymosin-alpha (ProTalpha) was identified to interact with the amino terminal half of tyrosine-phosphorylated STAT3.

Additional proteins in BAL fluid of Metsovites environmentally exposed to asbestos: more evidence of "protection" against neoplasia?

Introduction: Inhabitants of Metsovo in northwest Greece have been exposed to asbestos from use of a tremolite-containing whitewash ("luto" soil). As a result, they have increased incidence of malignant pleural mesothelioma and pleural calcifications (PCs). However, subjects with calcifications have a much lower incidence of mesothelioma than those without.

Nuclear distribution of prothymosin alpha and parathymosin: evidence that prothymosin alpha is associated with RNA synthesis processing and parathymosin with early DNA replication.

Prothymosin alpha and parathymosin are two ubiquitous small acidic nuclear proteins that are thought to be involved in cell cycle progression, proliferation, and cell differentiation. In an effort to investigate the molecular function of the two proteins, we studied their spatial distribution by indirect immunofluorescence labeling and confocal scanning laser microscopy in relation to nuclear components involved in transcription, translation, and splicing. Results indicate that both proteins exhibit a punctuated nuclear distribution and are excluded by nucleoli.

Prothymosin alpha modulates the interaction of histone H1 with chromatin.

Prothymosin alpha (ProTalpha) is an abundant acidic nuclear protein that may be involved in cell proliferation. In our search for its cellular partners, we have recently found that ProTalpha binds to linker histone H1. We now provide further evidence for the physiological relevance of this interaction by immunoisolation of a histone H1-ProTalpha complex from NIH 3T3 cell extracts.

Regulation of prothymosin alpha during the cell cycle.

A number of studies have indicated that the small nuclear acidic protein prothymosin alpha is associated with cellular-proliferation events. For example, c-myc causes immediate transcriptional activation of prothymosin alpha, and prothymosin alpha antisense oligonucleotides inhibit myeloma cell division. To investigate the regulation of prothymosin alpha, we examined its mRNA and protein levels during the cell cycle of mononuclear cells and fibroblastic cells.

Prothymosin alpha mRNA levels vary with c-myc expression during tissue proliferation, viral infection and heat shock.

Expression of prothymosin alpha, an acidic nuclear protein implicated in cellular proliferation, has been reported to be regulated by c-myc in vitro. We have studied the correlation of expression levels between prothymosin alpha and c-myc, using three different in vivo systems, viz. normal ontogenic process of placental development, lytic viral infection and heat shock treatment.

Prothymosin alpha gene in humans: organization of its promoter region and localization to chromosome 2.

A genomic clone encoding prothymosin alpha (gene symbol: PTMA), a nuclear-targeted protein associated with cell proliferation, was isolated and the 5'-regulatory region subcloned and sequenced. Because of previously reported discrepancies between several cDNA clones and a genomic clone for prothymosin alpha, we determined the sequence of the first exon and of a 1.7-kb region 5' to the first exon.

Appearance of thymosin alpha 1 in supernatants of monocytes incubated with prothymosin alpha.

Prothymosin alpha, a polypeptide of 109 to 111 amino acid residues, contains the entire thymosin alpha 1 sequence (residues 1-28) at its amino terminal. Human peripheral blood monocytes incubated with prothymosin alpha release thymosin alpha 1 in the culture supernatants. In addition total RNA is found to increase.

Isolation and partial sequence of goat spleen prothymosin alpha.

Goat prothymosin alpha, a highly acidic polypeptide of pI3.5, 109 amino acid residues, has been isolated from lymphoid and non-lymphoid tissues of young female goats. Unlike rat, murine and porcine prothymosins alpha, goat prothymosin alpha appears at a higher concentration in the spleen compared with the thymus.

Prothymosin alpha and parathymosin: mRNA and polypeptide levels in rodent tissues.

Blot hybridization analyses have established the presence of mRNAs for prothymosin alpha (ProT alpha) and for parathymosin (ParaT) in rat and mouse lung, liver, kidney, and brain, confirming the biosynthesis of these peptides in nonlymphoid tissues. In these tissues the levels of mRNAs paralleled the content of the polypeptides, determined with specific radioimmunoassays. The mRNA levels also confirmed the reciprocal relation between the two polypeptides; ProT alpha and its mRNA were found in highest concentrations in spleen and thymus, followed by lung, kidney, and brain, with lowest concentrations in liver.

The sequence of human parathymosin deduced from a cloned human kidney cDNA.

The amino acid sequence of human parathymosin has been deduced from the cDNA sequence of a clone isolated from a human kidney cDNA library. Screening of the cDNA library with a probe containing a partial rat cDNA sequence yielded two clones containing inserts of 1200 and 1100 base pairs respectively, each including the complete open reading frame for human parathymosin. The open reading frame contains 306 nucleotides, including the codon for the initiator methionine.

Isolation and partial characterization of prothymosin alpha from porcine tissues.

Prothymosin alpha, an immunoactive polypeptide of 12 kDa, has been isolated from porcine thymus, spleen, lung and kidney. It lacks aromatic and sulfur-containing amino acids and has a high content of glutamic and aspartic acids. Tryptic digestion of porcine thymus prothymosin alpha yielded peptides which on separation, amino acid analysis and alignment with the known sequence of prothymosin alpha from rat and man showed that the amino terminal portion of the molecule is conserved and the few differences present are confined to the carboxy terminal.

Prothymosin alpha and parathymosin: amino acid sequences deduced from the cloned rat spleen cDNAs.

A rat spleen cDNA library was screened for clones carrying the cDNAs for prothymosin alpha and parathymosin. Sequence analysis of a clone carrying the entire coding region for prothymosin alpha confirmed and completed the amino acid sequence for this polypeptide and established the number of amino acid residues as 111. Rat prothymosin alpha differs from human prothymosin alpha at six positions, including four substitutions and two insertions.

Effect of gramicidin S on the transcription system of the producer Bacillus brevis Nagano.

The effect of the peptide antibiotic gramicidin S, produced by Bacillus brevis Nagano, was tested on the transcription system of the producer by using in vivo, semi in vitro and in vitro systems for studies of RNA synthesis. The effects of other peptide antibiotics (linear gramicidin, tyrocidine and tyrothricin) were also tested for comparison. It was found that (a) RNA polymerase isolated from either gramicidin S-producing or non-producing strains had a similar structure and requirements and that (b) the presence of gramicidin S caused a very strong inhibition of the in vitro transcription system.