Identification of ionizing radiation-responsive microRNAs in the IM9 human B lymphoblastic cell line.
Ionizing radiation (IR) disrupts cellular homeostasis through multiple mechanisms including changes of the expression profile of genes. Although microRNAs (miRNAs), small single-stranded RNAs, have recently been recognized as important post-transcriptional regulators of gene expression, it is not well investigated if miRNAs function in the cellular response to radiation. Therefore, we determined if IR induces changes in the expression profiles of miRNAs and used this approach to identify IR-responsive miRNAs. To monitor the profiles of miRNAs, microarray analysis was conducted with irradiated IM9 human lymphoblastic cells. The expression levels of specific miRNAs were confirmed by quantitative real-time PCR (qRT-PCR) and statistically analyzed. Finally, the target mRNAs of some IR-responsive miRNAs were predicted with two different prediction programs. IR-exposed human lymphoblastic cells underwent cell cycle arrest and apoptosis. Apoptosis was more significantly increased at a higher radiation dose. There were 73 and 33 human miRNAs in 1 and 10 Gy-irradiated cells, respectively that showed expression level changes of >2-fold. By qRT-PCR analysis, it was revealed that the patterns of miRNA expression were similar to those observed in the microarray data, although the quantitative expression levels were discordant. Prediction of genes targeted by IR-responsive miRNA yielded several genes, many of which are involved in the regulation of apoptosis, the cell cycle, and DNA repair. The expression profiles of miRNAs in the IM9 human B lymphoblastic cells are strongly affected by IR and these changes may be involved in the regulation of cellular response to IR.
Functional Genoproteome Research Centre, Konkuk University, Seoul 143-701, Korea.
Hwa Jun
HJ
Cha
Sangsu
S
Shin
Hoesook
H
Yoo
Eun-Mee
EM
Lee
Seunghee
S
Bae
Kwang-Hee
KH
Yang
Su-Jae
SJ
Lee
In-Chul
IC
Park
Young-Woo
YW
Jin
Sungkwan
S
An
D019295:Computational Biology; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000528:radiation effects*; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects*; D008223:Lymphoma / Q000235:genetics*; D035683:MicroRNAs / Q000502:physiology* / Q000528:radiation effects*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011839:Radiation, Ionizing; D020133:Reverse Transcriptase Polymerase Chain Reaction
D035683:MicroRNAs; D012333:RNA, Messenger