Identification of Targets and Pathways Controlled by the Chicken MicroRNAs miR-10a and miR-143
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Date
2009-12-02
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Abstract
MicroRNAs are small non-coding RNAs that regulate gene expression at the posttranscriptional
level. The importance of microRNAs in development, tumorogenesis, immune
system function, and infectious diseases has gradually come to light. MicroRNAs are often
expressed in a temporal and spatial manner and regulate specific gene sets to achieve
phenotypic change. To understand the role of microRNAs in the chicken embryonic spleen,
we have profiled microRNA expression at E15 and E20 chicken embryos. The objective of
the current project is to identify the targets and pathways controlled by two microRNAs,
miR-10a and miR-143. Target prediction was carried out by the algorithm miRanda. Eight
predicted targets of each microRNA were subjected to validation using a reporter assay that
incorporates synthetic or retroviral transduced microRNA. Validated targets for miR-143
known to have profound functions in apoptosis, T and B cell development and maturation,
cancer, or adipocyte differentiation were identified with this approach; for miR-10a,
validated targets involved in hematopoiesis, immune cells homing and migration and
megakaryocyte differentiation were identified. Microarray analysis revealed that several
targets not predicted by the algorithm were upregulated upon treatment with a specific
microRNA inhibitor. This result suggests that both microRNAs may regulate genes that
contribute to cancer formation. In addition, miR-10a may be involved in regulating the
complement system, which is a crucial component of innate immunity; miR-143 may be
involved in the PPAR/RXR pathway, which regulates glucose and lipid metabolism in cells.
Taken together, our results suggest targets and pathways possibly regulated by miR-10a or
miR-143. The inferred functions of the targets and pathways identified in our study are
mostly consistent with those from previous studies, thereby providing insights and directions
for future research into the mechanisms by which miR-10a and miR-143 exert their function
in the developing chick embryo. Furthermore, the RCAS system used in this project also
proved the usefulness of engineered retrovirus for transducing microRNA. Further
development of this tool may aid microRNA research and further contribute to understanding
of the role of microRNAs in vertebrate development.
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Keywords
spleen, chicken, microRNA, luciferase assay, microarray
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Degree
MS
Discipline
Animal Science