Distribution of prothymosin alpha in rat tissues.

Abstract

A radioimmunoassay, using a rabbit antiserum directed against thymosin a,, was employed to detect the presence of crossreacting peptides in rat tissues. Highest concentrations were present in thymus, but thymosin al crossreacting material was also detected in brain, liver, kidney, lung, and spleen, in amounts ranging from 15% to 65% of the quantities found in thymus. In each case, the major immunoreactive peptide, after extraction and purification by a procedure that avoids proteolytic modification, was identified as prothymosin a, a peptide containing %112 amino acid residues. Prothymosin a is believed to be the endogenous peptide from which thymosin a, and other fragments are formed by proteolytic modification during the preparation of thymosin fraction 5. No peptides corresponding in size and chromatographic behavior to thymosin a, were detected with the extraction procedure employed.

Characterization of two thymosins as immune-related genes in common carp (Cyprinus carpio L.)

“…Moreover, the expression levels of carp ProTα b and Tβ-l were lower in thymus when compared with that of other tissues. It seems to be controversial with previous study in which high expression of thymosins were found in mammalian thymus (Haritos et al, 1984). Although thymosins were firstly isolated from mammalian thymus tissue preparations, their occurrences were not tissue-specific and they were even present in different types of cells (Mihelic and Voelter, 1994).…”

The human prothymosin alpha gene is polymorphic and induced upon growth stimulation: evidence using a cloned cDNA.

“…These residues, located at positions 20-21 and 103-104 (lysine, lysine) and at position 89-90 (lysine, arginine) of the human, are utilized in other systems as processing signals for the conversion of precursor polypeptides to mature products (34 examined, including the thymus, when denaturing conditions were maintained during protein isolation. Significant levels of prothymosin a were found in rat thymus, brain, liver, lung, and kidney under these conditions (35). They and others found peptides only when a crude thymic extract known as thymosin fraction 5 or isotonic conditions (36) were employed as part of the protocol.…”

Prothymosin α in Vivo Contains Phosphorylated Glutamic Acid Residues

“…32 P-Protein in dried gels was imaged directly with X-AR x-ray film (Kodak). 3 H-Protein was visualized by soaking fixed gels in Enlightning (NEN Life Science Products) according to the accompanying instructions, drying the gels, and exposing them to film. In both cases, gels were stained with Coomassie Brilliant Blue; quantitative evaluations of stained and autoradiographed proteins were obtained with a Molecular Dynamics Personal Laser Densitometer.…”

“…The protein is neither a precursor for processed polypeptides nor specifically associated with the thymus nor a member of a family with ␤ or ␥ homologues (1)(2)(3). Instead, it is probably the most acidic naturally occurring polypeptide in the eukaryotic world, with 54 carboxyl groups in 109 amino acids, resulting in an isoelectric point at or below pH 3.5 (1,2,4).…”