ABSTRACT Chen et al Toxicol Sci, May 2000

[Jim Muckerheide <jmuckerheide@delphi.com>]

Group,

http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10788564&dopt=Abstract

An ascii version below.

Please let me know if you have access to this paper and can send a copy?

Regards, Jim
muckerheide@mediaone.net
Radiation, Science, and Health
==============================


Toxicol Sci 2000 May;55(1):97-106
 
Low-Dose Whole-Body Irradiation (LD-WBI) Changes Protein Expression of Mouse
Thymocytes: Effect of a LD-WBI-Enhanced Protein RIP10 on Cell Proliferation
and Spontaneous or Radiation-Induced Thymocyte Apoptosis. 

 Chen SL, Cai L, Meng QY, Xu S, Wan H, Liu SZ 

 Low-dose radiation (LDR) can potentiate cellular metabolic activities or
immune functions in vivo (hormesis), and can render cells resistant to DNA or
chromosome damage caused by subsequent high-dose radiation (adaptive
response). Protein synthesis was required for these cellular responses to LDR.
In the present study, the early expression of proteins by thymocytes in
response to low-dose whole-body irradiation (LD-WBI) was investigated. The
expression of novel and previously existing proteins was found in the nucleus,
cytoplasm, and extracellular fluid of thymocytes at 4 hours after WBI with
75-mGy X-rays. A 10 kD protein (RIP10) was seen in the cytoplasm of thymocytes
after LD-WBI was further investigated. The fraction containing RIP10 separated
by Sephadex G 100 gel filtration potentiated spontaneous thymocyte, and
mitogen-induced splenocyte proliferation. Western blotting demonstrated that
an anti-RIP10 antibody could react with a 10-kD cytoplasm protein and also
with a 13-kD nuclear protein in thymocytes at 4 h after LD-WBI.
Immunocytochemical staining showed the existence of RIP10 in several immune
tissues including thymus, spleen, and lymph node. RIP10 expression, as
determined by immunocytochemical staining and flow cytometry, was enhanced at
4-8 h after LD-WBI. Cell-cycle arrest (G(0)/G(1) block with decreased
percentage of S-phase cells), and increased levels of spontaneous or
radiation-induced apoptosis were observed in thymocytes incubated with RIP10
antibody in vitro for 4 h or 24 h. These results directly demonstrated the
role of RIP10 in modulating cell proliferation and apoptosis. This finding is
important to understand the mechanisms underlying LDR-induced hormesis and
adaptive response.
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