Supplementary MaterialsS1 Video: Developmental innervation of hair cells by a singly marked axon. mature hair cells expressing EGFP (green) by a previously severed single axon marked by mosaic expression of mCherry (reddish). Basal projections are not produced by these hair cells. Yet synaptogenesis occurs normally. Thin green extensions towards the end of the video are apical kinocilia from your hair cells, which become obvious due to their free movement. EGFP, enhanced green fluorescent protein.(AVI) pbio.2004404.s002.avi (1.3M) GUID:?29F3CA17-EDCE-44C8-B688-6F814572292D S3 Video: Determination of synapses in a horizontal neuromast by individualized axon before severing. This video is usually a Z-stack used to generate panel PCP of Fig 3 and shows an example of the innervation of mature hair cells expressing EGFP (green) by an axon marked by mosaic expression of mCherry (reddish). Red dots show the synapsed hair cells, whose planar polarization is usually evident in the most apical aspect of the epithelium (beginning of the video), exposing their caudorostral orientation (as depicted in Fig 3Q). Yellow arrows show synaptic contacts as bulged axon endings. EGFP, enhanced SB 203580 green fluorescent protein.(AVI) pbio.2004404.s003.avi (1.1M) GUID:?4DCBCA33-6EDA-4DAC-A84C-17E60BB108C2 S4 Video: Determination of synapses by the individualized axon that initially innervated the horizontal neuromast, after severing and regeneration to innervate a vertical neuromast. This video is usually a Z-stack used to generate panel RCR of Fig 3 and shows an example of the re-innervation of mature hair cells expressing EGFP (green) by an axon marked by mosaic expression of mCherry (reddish). Red dots show the synapsed hair cells, whose planar polarization is usually evident in the most apical aspect of the epithelium (beginning of the video), exposing their ventrodorsal orientation (as depicted in Fig 3S). EGFP, enhanced green fluorescent protein.(AVI) pbio.2004404.s004.avi (1.0M) GUID:?D3DDC21B-4779-4813-B441-3B995D2A34E0 S5 Video: Assessment of Emx2 immunostaining. This video shows an example of a Z-stack of a neuromast immunostained for Emx2. White circles mark 5 Emx2(+) hair cells (magenta). Figures reflect order of appearance across the Z-stack from your epithelial apex to base. This Z-stack was used to generate the maximal-projection image shown in Fig 4K and is exemplified in drawing of Fig 4L.(AVI) pbio.2004404.s005.avi (603K) GUID:?9856E1BB-E0F9-4A5F-9234-CF44B1696AC5 S1 Table: Numerical data for the plots in Fig 5. This table contains the data point utilized for statistical assessments plotted in VEGFA Fig 5E (left) and Fig 5L (right), including all conditions that include wild-type and mutant specimens.(TIFF) pbio.2004404.s006.tiff (1.0M) GUID:?82B05B9A-280F-4660-89BA-BC48B1CBB17C Data Availability StatementAll relevant data are SB 203580 within the paper and its Supporting SB 203580 information files. Abstract Directional mechanoreception by hair cells is usually transmitted to the brain via afferent neurons to enable postural control and rheotaxis. Neuronal tuning to individual directions of mechanical flow occurs when each peripheral axon selectively synapses with multiple hair cells of identical planar polarization. How such mechanosensory labeled lines are established and managed remains unsolved. Here, we use the zebrafish lateral collection to reveal that asymmetric activity of the transcription factor Emx2 diversifies hair cell identity to instruct polarity-selective synaptogenesis. Unexpectedly, presynaptic scaffolds and coherent hair cell orientation are dispensable for synaptic selectivity, indicating that epithelial planar polarity and synaptic partner matching are separable. Moreover, regenerating axons recapitulate synapses with hair cells according to Emx2 expression but not global orientation. Our results identify a simple cellular algorithm that solves the selectivity task even in the presence of noise generated by the frequent receptor cell turnover. They also suggest that coupling connectivity patterns to cellular identity rather than polarity relaxes developmental and evolutionary constraints to innervation of organs with differing orientation. Author summary Mechanosensory systems are essential for maintaining posture, gaze, and body orientation during locomotion. Such stability requires a coherent representation in the brain of the location and movement of mechanical stimuli. In fishes,.