Abstract
The outer hair cells (OHCs) are the sensory cells in the mammalian cochlea of the inner ear. They exhibit elongation and contraction in response to acoustical stimulation. Due to this somatic motility, the basilar membrane is subjected to force, resulting in cochlear amplification and thus leading to the high sensitivity of mammalian hearing. This motility is thought to be driven by a motor protein embedded in the lateral wall of OHCs. In 2000, this motor protein was identified and termed prestin. Prestin consists of 744 amino acids with a molecular weight of about 81.4 kDa. In a series of attempts to clarify its membrane topology, hydrophobicity analysis in conjunction with the prediction of the conserved phosphorylation site has suggested that prestin is a 10 or 12 transmembrane protein with cytoplasmic N- and C-termini. The size of prestin was reported to be about 10 nm in diameter, presumably forming tetramer. For the further progress on prestin research at molecular level, it is indispensable to develop a method of obtaining a large amount of prestin. In this study, therefore, an attempt was made to construct an expression system for prestin. For that, a mammalian expression vector containing prestin cDNA was developed. After the amount of such vector was amplified with Escherichia coli (E. coli), its existence was confirmed by electrophoresis and sequence analysis. Results showed that the mammalian expression vector of prestin was properly developed.
