MicroRNA-206 Regulates Cell Movements during Zebrafish Gastrulation by Targeting prickle1a and Regulating c-Jun N-Terminal Kinase 2 Phosphorylation

During vertebrate gastrulation, both concurrent inductive events and cell movements are required for axis formation. Convergence and extension (CE) movements contribute to narrowing and lengthening the forming embryonic axis. MicroRNAs (miRNAs) play a critical role in regulating fundamental cellular functions and developmental processes, but their functions in CE movements are not well known. Zebrafishmir206 is maternally expressed and present throughout blastulation and gastrulation periods. Either gain or loss of function ofmir206 leads to severe defects of convergent extension movements both cell autonomously and non-cell autonomously. Mosaic lineage tracing studies reveal that the formation of membrane protrusions and actin filaments is disturbed inmir206 -overexpressing embryos ormir206 morphants. Mechanistically,mir206 targetsprickle1a (pk1a ) mRNA and as a result regulates c-Jun N-terminal protein kinase 2 (JNK2) phosphorylation.pk1a overexpression or knockdown can rescue convergent extension defects induced bymir206 overexpression or knockdown, respectively. Therefore,mir206 is an essential, novel regulator for normal convergent and extension movements by regulating mitogen-activated protein kinase (MAPK) JNK signaling.