The expression of p53-regulated genes in human cultured lymphoblastoid TSCE5 and WTK1 cell lines during spaceflight.
OBJECTIVE
The space environment contains two major biologically significant influences; space radiations and microgravity. The 53 kDa tumour suppressor protein (p53) plays a role as a guardian of the genome through the activity of p53-centered signal transduction pathways. The aim of this study was to clarify the biological effects of space radiations, microgravity, and the space environment on the gene expression of p53-regulated genes.


METHODS
Space experiments were performed with two human cultured lymphoblastoid cell lines; one line (TSCE5) bears a wild-type p53 gene status, and another line (WTK1) bears a mutated p53 gene status. Under one gravity or microgravity conditions, the cells were grown in the cell biology experimental facility (CBEF) of the International Space Station for 8 days without experiencing stress during launching and landing because the cells were frozen during these periods. Ground control samples also were cultured for 8 days in the CBEF on the ground during the spaceflight. Gene expression was analysed using an Agilent Technologies 44 k whole human genome microarray DNA chip.


RESULTS
p53-dependent up-regulated gene expression was observed for 111, 95, and 328 genes and p53-dependent down-regulated gene expression was found for 177, 16, and 282 genes after exposure to space radiations, to microgravity, and to both, respectively.


CONCLUSIONS
The data provide the p53-dependent regulated genes by exposure to radiations and/or microgravity during spaceflight. Our expression data revealed genes that might help to advance the basic space radiation biology.
Takahashi
Akihisa
A
Department of Biology, School of Medicine, Nara Medical University, Kashihara, Nara, Japan.
Suzuki
Hiromi
H
Omori
Katsunori
K
Seki
Masaya
M
Hashizume
Toko
T
Shimazu
Toru
T
Ishioka
Noriaki
N
Ohnishi
Takeo
T
D002460:Cell Line; D020869:Gene Expression Profiling; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D013026:Space Flight; D016159:Tumor Suppressor Protein p53 / Q000502:physiology*; D014893:Weightlessness
D016159:Tumor Suppressor Protein p53