動物的三個身體軸是在發(fā)育過程中依次形成的——先是前-后軸和背-腹軸,，然后是左-右非對稱性,，但后者是怎樣源自前者的卻不清楚。現(xiàn)在,，Yingzi Yang及其同事發(fā)現(xiàn),，屬于“planar cell polarity”家族的兩個小鼠基因(Vangl1 和 Vangl2) 是纖毛在身體后部沉積所必需的，后者又決定穿過后部脊索的左向“節(jié)流動”,。
這項工作表明,，平面細(xì)胞極性是一個在演化過程中保留下來的機(jī)制，它傳輸預(yù)先確定的前-后位置信息，并將其轉(zhuǎn)換成胚胎中第一個打破側(cè)向?qū)ΨQ的事件,。(生物谷Bioon.net)
生物谷推薦原文出處：
Nature doi:10.1038/nature09129
Planar cell polarity breaks bilateral symmetry by controlling ciliary positioning
Hai Song Jianxin Hu Wen Chen Gene Elliott Philipp Andre Bo Gao Yingzi Yang
Defining the three body axes is a central event of vertebrate morphogenesis. Establishment of left–right (L–R) asymmetry in development follows the determination of dorsal–ventral and anterior–posterior (A–P) body axes1, 2, although the molecular mechanism underlying precise L–R symmetry breaking in reference to the other two axes is still poorly understood. Here, by removing both Vangl1 and Vangl2, the two mouse homologues of a Drosophila core planar cell polarity (PCP) gene Van?Gogh (Vang), we reveal a previously unrecognized function of PCP in the initial breaking of lateral symmetry. The leftward nodal flow across the posterior notochord (PNC) has been identified as the earliest event in the de novo formation of L–R asymmetry3, 4. We show that PCP is essential in interpreting the A–P patterning information and linking it to L–R asymmetry. In the absence of Vangl1 and Vangl2, cilia are positioned randomly around the centre of the PNC cells and nodal flow is turbulent, which results in disrupted L–R asymmetry. PCP in mouse, unlike what has been implicated in other vertebrate species, is not required for ciliogenesis, cilium motility, Sonic hedgehog (Shh) signalling or apical docking of basal bodies in ciliated tracheal epithelial cells. Our data suggest that PCP acts earlier than the unidirectional nodal flow during bilateral symmetry breaking in vertebrates and provide insight into the functional mechanism of PCP in organizing the vertebrate tissues in development.
