The Role Of Slc4a2b Gene In Zebrafish Hair Cell Development And Function

Hearing is one of the most important sensory function.Hearing loss or deafness would greatly affect our daily life and lower the quality of our life.In mammals including humans,the organ of hearing is the ear,which can be divided into three parts,external ear,middle ear and inner ear.The cochlear hair cells,the key members in the inner ear,can sense the acoustic signals and transmit them to the nervous system.Any factors leading to cochlear hair cell damage would cause hearing loss,or even deafness.The main factors that cause hearing loss include acoustic trauma,ototoxic drug treatments and genetic factors.Hereditary deafness is caused by the gene mutations,and can be inherited to the next generation.At present,more than 200 deafness genes have been discovered,but there are still a large number of deafness genes waiting to be identified.Therefore,the continuous discovery of deafness genes plays a very important role for a better understanding of the pathogenic mechanism,prevention and treatment of hereditary hearing loss.Here,we took the zebrafish as the animal model,and obtained many of candidate genes which specifically expressed in the zebrafish hair cells using single-cell RNA-sequencing(sc RNA-seq)method,including the deafness genes that had been confirmed.The zebrafish solute carrier family 4,member 2b(slc4a2b)gene,which encoding a solute transport protein,is one of the many genes screened by this method.Through gene conservation analysis,we found that the slc4a2 b gene is highly conserved in evolution.In addition,in situ hybridization experiments revealed that the slc4a2 b gene was specifically expressed in the zebrafish otic vesicle and lateral line neuromasts.Next,we constructed slc4a2 b gene knockdown and mutant zebrafish models through morpholino oligonucleotide(MO)-mediated gene knockdown technology and CRISPR/Cas9 gene editing technology,respectively.According to the results,we found that loss of function of the slc4a2 b gene resulted in the decrease of the lateral line neuromast hair cells in zebrafish.Further analysis showed that loss of function of slc4a2 b gene led to caspase-3 mediated apoptosis in hair cells.In summary,the slc4a2 b gene plays an important role in the development and function of hair cells in zebrafish.These results can provide experimental evidence for the clinical discovery of hair cell-related diseases caused by SLC4A2 gene deficiency and provide ideas for the discovery of deafness genes.