Temporal and Spatial Expression Patterns of miR-302 and miR-367 During Early Embryonic Chick Development

Abstract

The microRNAs (miRNAs) are small, non-coding RNAs that modulate protein expression by interfering with targetmRNA translation or stability. miRNAs play crucial roles in various functions such as cellular, developmental, andphysiological processes. The spatial expression patterns of miRNAs are very essential for identifying their functions.The expressions of miR-302 and miR-367 are critical in maintaining stemness of pluripotent stem cells, includingembryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) but their functions in early development arenot fully elucidated. So, we used Locked Nucleic Acid (LNA) probes to perform in situ hybridization and confirmedthe temporal and spatial distribution patterns during early chick development. As a result, we found that miR-302and miR-367 were expressed in various tissues such as primitive steak, neural ectoderm, neural plate, neural fold,neural tube, notochord, and oral cavity. Specially, we confirmed that miR-302 and miR-367 were strongly expressedin neural folds in HH8 to HH10. miR-302 was expressed on dorsal part of the neural tube but miR-367 was expressedon lateral and ventral parts of the neural tube. And also we performed quantitative stem-loop real-time PCR to analyzeglobal expression level of miR-302 and miR-367. miR-302 and miR-367 expression was sustained before Hamburgerand Hamilton stage (HH) 14. Thus, the temporal and spatial expression patterns of miR-302 and miR-367 may provideus information of the role of these miRNAs on tissue formation during early chick development.