Contributions of mirror-image hair cell orientation to mouse otolith organ and zebrafish neuromast function: Part 2/2, Hair cell and afferent physiology from mouse utricle
Data files
Nov 15, 2024 version files 71.94 KB
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F2_FS2_sourcedata.xlsx
15.70 KB
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F3_FS3_sourcedata.xlsx
19.38 KB
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F4_FS4_sourcedata.xlsx
17.74 KB
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F8_FS5_sourcedata.xlsx
12.18 KB
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README.md
6.95 KB
Abstract
Otolith organs in the inner ear and neuromasts in the fish lateral-line harbor two populations of hair cells oriented to detect stimuli in opposing directions. The underlying mechanism is highly conserved: the transcription factor EMX2 is regionally expressed in just one hair cell population and acts through the receptor GPR156 to reverse cell orientation relative to the other population. In mouse and zebrafish, loss of Emx2 results in sensory organs that harbor only one hair cell orientation and are not innervated properly. In zebrafish, Emx2 also confers hair cells with reduced mechanosensory properties. Here, we leverage mouse and zebrafish models lacking GPR156 to determine how detecting stimuli of opposing directions serves vestibular function, and whether GPR156 has other roles besides orienting hair cells. We find that otolith organs in Gpr156 mouse mutants have normal zonal organization and normal type I-II hair cell distribution and mechano-electrical transduction properties. In contrast, gpr156 zebrafish mutants lack the smaller mechanically-evoked signals that characterize Emx2-positive hair cells. Loss of GPR156 does not affect orientation-selectivity of afferents in mouse utricle or zebrafish neuromasts. Consistent with normal otolith organ anatomy and afferent selectivity, Gpr156 mutant mice do not show overt vestibular dysfunction. Instead, performance on two tests that engage otolith organs is significantly altered – swimming and off-vertical-axis rotation. We conclude that GPR156 relays hair cell orientation and transduction information downstream of EMX2, but not selectivity for direction-specific afferents. These results clarify how molecular mechanisms that confer bi-directionality to sensory organs contribute to function, from single hair cell physiology to animal behavior.
https://doi.org/10.5061/dryad.905qfttvj
Description of the data and file structure
This dataset is from the mouse utricle, comparing control tissue with tissue lacking the normal line of reversal of hair bundle polarity (LPR). Data included are: whole-cell patch clamp data on hair cell transduction and voltage-gated current properties (Figure 2 and its associated supplementary file 2, F2-FS2; Figure 3 and supplementary file 3, F3-FS3; Figure 4 and supplementary file 4, F4-FS4) and vestibular afferent properties (Figure 8 and supplementary file 5, F8-FS5).
Datasets are in excel format. Datasets have headers, and additional information is provided in this document.
DATA & FILE OVERVIEW
Each file corresponds to a parent figure and a Figure supplement containing a table in the manuscript, and contains sufficient data to recreate all statistical tests. Each file contains sheets that are explicitly labelled to refer to condition (cell type, genotype) within that table. Each sheet has header information describing the parameter, condition (genotype, age, zone), and the unique Cell ID of every cell used in the analysis. Some data is repeated in different files if it is used in multiple figures or tables. This is seen if when the unique Cell ID for each data entry is found in multiple files.
Files and variables
Additional information for some sheets within files is provided below.
Filename: F2_FS2_sourcedata.xlsx
Sheetname: FS2_Gpr156_HET, FS2_Gpr156_KO
Description: The sheets named “FS2_Gpr156_HET” and “FS2Gpr156KO” include the data from Gpr156+/- and Gpr156-/- mice, used to generate Figure Supplement 2, respectively. “none” in the cells indicates that the adaptation component was not detectable by exponential curve fitting. The sheet named “F2_Representatives” includes representative Cell IDs used to generate Figure panels.
Number of Variables: 19
- Cell ID: Unique cell identifier
- Cell type: type I (HCI) or type II (HCII) hair cell
- Age: postnatal day (P)
- Sex: male (m) or female (f)
- tau Vfast: ms, time constant for very fast adaptation component at X1/2
- tau fast: ms, time constant for fast adaptation component at X1/2
- tau slow: ms, time constant for slow adaptation component at X1/2
- OR: nm, 10%~90% operating range of hair bundle
- Imax: pA, Maximum peak mechano-electrical transduction (MET) current evoked by step-bundle displacement
- % decay: percentage, extent to which I-MET adapts
- X1/2: micrometer, displacement that evokes half-maximal I-MET
- dx: micrometer, displacement corresponding to an e-fold rise in I-MET
- Probe scale f: micrometer/V, scale factor of the rigid probe motion
- A1 amplitude: pA, amplitude of very fast adaptation component at X1/2
- A2 amplitude: pA, amplitude of fast adaptation component at X1/2
- A3 amplitude: pA, amplitude of slow adaptation component at X1/2
- A1 amplitude: %, proportion of very fast adaptation component to overall adaptation at X1/2
- A2 amplitude: %, proportion of fast adaptation component to overall adaptation at X1/2
- A3 amplitude: %, proportion of slow adaptation component to overall adaptation at X1/2
Filename: F3_FS3_sourcedata.xlsx
Sheetname: FS3_HCI, FS3_HCII
Description: The sheets named “FS3_HCI” and “FS3_HCII” include the data for type I and type II hair cells used to generate Figure Supplement 3, respectively. The sheet named “F3_Representatives” includes representative Cell IDs used to generate Figure panels. Any blank cells in the file indicate a lack of data for that variable.
Number of Variables: 10
- Cell ID: Unique cell identifier
- Genotype: Gpr156 knockouts (KO) or heterozygote control (HET)
- Age: postnatal day (P)
- Sex: male (m) or female (f)
- Cm: pF, Cell membrane capacitance
- Vrest: mV, resting potential
- V1/2: mV, half maximal activating potential
- Slope F: mV, the voltage change over which conductance (G) changes e-fold at voltages negative to V1/2
- Rin: megaOhms, the input resistance
- Gmax/Cm: nS/pF, conductance density
Filename: F4_FS4_sourcedata.xlsx
Sheetname: FS4_Gpr156_HET, FS4_Gpr156_KO
Description: The sheets named “FS4_Gpr156_HET” and “FS4_Gpr156_KO” include the data for Gpr156 heterozygote control and Gpr156 knockouts used to generate Figure Supplement 4, respectively. “none” in the cells indicates that the adaptation component was not detectable by exponential curve fitting. The sheet named “F4_Representatives” includes representative Cell IDs used to generate Figure panels.
Number of Variables: 17
- Cell ID: Unique cell identifier
- Zone: Location of the cell within utricle; LES, MES or Striola
- Cell type: type I (HCI) or type II (HCII) hair cell
- Age: postnatal day (P)
- Sex: male (m) or female (f)
- tau Vfast: ms, time constant for very fast adaptation component at X1/2
- tau fast: ms, time constant for fast adaptation component at X1/2
- tau slow: ms, time constant for slow adaptation component at X1/2
- OR: nm, 10~90% operating range of hair bundle
- Imax: pA, Maximum peak mechano-electrical transduction (MET) current evoked by step-bundle displacement
- % decay: percentage, extent of I-MET adaptation
- X1/2: micrometer, displacement that evokes half-maximal I-MET
- dx: micrometer, displacement corresponding to an e-fold rise in I-MET
- Probe scale f: micrometer/V, scale factor of the rigid probe motion
- A1 amplitude: %, proportion of very fast adaptation component to overall adaptation at X1/2
- A2 amplitude: %, proportion of fast adaptation component to overall adaptation at X1/2
- A3 amplitude: %, proportion of slow adaptation component to overall adaptation at X1/2
Filename: F8_FS5_sourcedata.xlsx
Sheetname: FS5
Description: The sheet named “FS5” includes the data from calyceal endings used to generate Figure Supplement 5. The sheet named “F8_Representatives” includes representative Cell IDs used to generate Figure panels.
Number of Variables: 8
- Cell ID: Unique cell identifier
- Genotype: Gpr156 knockouts (KO) or heterozygote control (HET)
- Age: postnatal day (P)
- Sex: male (m) or female (f)
- Transient/Sustained: transient neuron (T) or sustained neuron (S) in response to adequate amount of current injection
- Vrest: mV, resting potential
- Rin: megaOhms, the input resistance
- I-threshold: pA, threshold step-current that elicited an initial spike
This dataset submission is linked with Part 1: DOI: https://doi.org/10.5061/dryad.m63xsj4br
We compared mechano-electrical transduction and whole-cell voltage-activated K+ currents in verstibular type I and type II hair cells from homozygous knockout (Gpr156–/–) animals and heterozygote (Gpr156+/–) littermates. We performed current clamp experiments to investigate firing properties of calyceal afferent nerves.