Developmental expression of the outer hair cell motor prestin in the mouse
Developmental expression of the outer hair cell motor prestin in the mouse
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DOI：
10.1007/s00232-007-9004-5
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发表时间：
2007-01-01
影响因子：
2.4
通讯作者：
Shinkawa, Hideichi
中科院分区：
文献类型：
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作者：
Abe, Takahisa;Kakehata, Seiji;Shinkawa, Hideichi
用全细胞电压钳技术研究了出生后5天（P5）至P18小鼠外毛细胞（OHC）侧膜运动蛋白活性的发育。电压依赖性，非线性电容（C（v）），这代表了电机分子的构象波动，在发展过程中逐步增加。在P12，小鼠听力的开始，C（v）约为成熟水平的70%。C（v）在P18时达到饱和，此时听力显示完全成熟。另一方面，代表OHC膜面积的C（lin）随着发育表现出相对较小的增加，在P10达到稳态。这种线性电容的早期成熟进一步得到了发育过程中表面积的形态学估计的支持。这些结果，根据最近的普雷斯廷基因敲除实验和我们的结果与定量聚合酶链反应，表明，而不是纳入新的马达到侧膜后P10，分子马达成熟，以增加非线性电容。因此，目前基于电荷运动对马达蛋白密度的估计可能被夸大了。运动成熟的相应指标，电机的工作电压中点，V（pkcm），往往转移到去极化电位在出生后的发展，虽然它是不稳定的P10之前。然而，在P14之后，V（pkcm）达到接近-67 mV的稳态水平，这表明可以调节V（pkcm）的内在膜张力或细胞内氯可能在P14成熟。这些发展数据显着改变了我们的理解，控制耳蜗放大的细胞机制，并提供了一个基础，为未来的分析遗传修饰的小鼠听觉发展。
The development of motor protein activity in the lateral membrane of the mouse outer hair cell (OHC) from postnatal day 5 (P5) to P18 was investigated under whole-cell voltage clamp. Voltage-dependent, nonlinear capacitance (C (v)), which represents the conformational fluctuations of the motor molecule, progressively increased during development. At P12, the onset of hearing in the mouse, C (v) was about 70% of the mature level. C (v) saturated at P18 when hearing shows full maturation. On the other hand, C (lin), which represents the membrane area of the OHC, showed a relatively small increase with development, reaching steady state at P10. This early maturation of linear capacitance is further supported by morphological estimates of surface area during development. These results, in light of recent prestin knockout experiments and our results with quantitative polymerase chain reaction, suggest that, rather than the incorporation of new motors into the lateral membrane after P10, molecular motors mature to augment nonlinear capacitance. Thus, current estimates of motor protein density based on charge movement may be exaggerated. A corresponding indicator of motor maturation, the motor's operating voltage midpoint, V (pkcm), tended to shift to depolarized potentials during postnatal development, although it was unstable prior to P10. However, after P14, V (pkcm) reached a steady-state level near -67 mV, suggesting that intrinsic membrane tension or intracellular chloride, each of which can modulate V (pkcm), may mature at P14. These developmental data significantly alter our understanding of the cellular mechanisms that control cochlear amplification and provide a foundation for future analysis of genetic modifications of mouse auditory development.