Zebrafish pax5 regulates development of the utricular macula and vestibular function
Su-Jin Kwak1, Shruti Vemaraju, Stephen J Moorman
1Biology Department, Texas A&M University, College Station, Texas, USA.
Summary
Pax5 is crucial for zebrafish vestibular function, ensuring utricular macula development and hair cell survival. Its absence disrupts balance but not hearing, highlighting its specific role in the inner ear.
Area of Science:
- Developmental biology
- Neuroscience
- Genetics
Background:
- The zebrafish otic vesicle contains two sensory epithelia: the utricular macula (vestibular) and saccular macula (auditory).
- Pax5 is preferentially expressed in the utricular macula, suggesting a specific role in vestibular function.
Purpose of the Study:
- To investigate the role of pax5 in the development and function of the zebrafish otic vesicle.
- To determine if pax5 is essential for utricular macula formation, hair cell survival, and vestibular function.
Main Methods:
- Morpholino knockdown of pax5 in zebrafish embryos.
- Assessment of vestibular and auditory function.
- Analysis of hair cell development, survival, and apoptosis in the otic vesicle.
- Examination of statoacoustic ganglion (SAG) neuron development and dendritic organization.
Main Results:
- Pax5 knockdown disrupted vestibular function but did not affect hearing.
- Utricular hair cells showed normal initial formation but subsequent apoptosis and extrusion.
- SAG neuron dendrites in the utricle became disorganized following hair cell loss.
- Saccular hair cell development and survival remained unaffected.
- Otic expression of pax5 was dependent on pax2a and fgf3.
Conclusions:
- Pax5 is essential for establishing and/or maintaining the utricular macula in zebrafish.
- Pax5 acts in conjunction with pax2a and fgf3 to ensure proper vestibular function.
- The findings highlight pax5's critical role in vestibular sensory development and hair cell maintenance.
