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Licensed Unlicensed Requires Authentication Published by De Gruyter June 1, 2005

On the Role of Thymopoietins in Cell Proliferation. Immunochemical Evidence for New Members of the Human Thymopoietin Family

P.J.A. Weber, C.P. Eckard, S. Gonser, H. Otto, G. Folkers and A.G. Beck-Sickinger
From the journal Biological Chemistry

Abstract

Thymopoietins (TMPOs) are a group of ubiquitously expressed nuclear proteins. They are suggested to play an important role in nuclear envelope organization and cell cycle control, as has been shown for lamina-associated polypeptides 2 α and β, which are the rat homologs of human TMPOα and TMPOβ, respectively. The recent isolation and characterization of seven mouse TMPO mRNA transcripts named TMPO-α, β, β', γ, ε, δ, and ζ, suggest that more than the three previously reported transcripts, α, β, and γ forms, may exist in humans. Here we report on the demonstration of putative human TMPOδ and ε by immunoblotting of human cell lines using a newly prepared polyclonal antiserum against the common N-terminal region of TMPO. Furthermore, we prepared the first truly TMPO-β-specific, affinity-purified polyclonal antiserum, using a part of the human analog of the β-specific domain of mouse TMPO 220–259 for immunization. We showed that human TMPOβ is highly expressed in all cancerous cells tested, while hardly any cross-reactivities with other proteins could be detected. In contrast to the high expression of human TMPOβ in the cancer-derived neuroblastoma cell lines SK-N-MC and SMS-KAN, we found very low expression of human TMPOβ in low-proliferative nerve tissue. These data led us to the assumption that expression of TMPOβ may correlate with the occurrence of cancer, and therefore may serve as a new tumor marker, or even as a new target for cancer therapy.

Published Online: 2005-6-1
Published in Print: 1999-6-1

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