CaV3.2 T-type channels mediate Ca2+ entry during oocyte maturation and following fertilization
CaV3.2 T-type channels mediate Ca2+ entry during oocyte maturation and following fertilization
复制标题
DOI：
10.1242/jcs.180026
复制
发表时间：
2015-12-01
影响因子：
4
通讯作者：
Williams, Carmen J.
中科院分区：
文献类型：
--
作者：
Bernhardt, Miranda L.;Zhang, Yingpei;Williams, Carmen J.
小鼠胚胎发育的启动依赖于一系列受精诱导的细胞内Ca2+的升高。卵子的完全激活需要细胞外Ca2+的流入；然而，调解这种流入的渠道仍然未知。在这里，我们测试了由Cacna1h编码的t型通道Ca(V)3.2的α 1亚基是否介导Ca2+进入卵母细胞。我们发现小鼠卵子表达一个强大的电压激活的Ca2+电流，这在Cacna1h（-/-）卵子中是完全不存在的。Cacna1h（-/-）雌性减少了产仔数，仔细分析Cacna1h（-/-）卵的Ca2+振荡模式，在体外受精（IVF）后发现了首次瞬态长度和振荡持久性的减少。Cacna1h（-/-）卵的总Ca2+和内质网（ER） Ca2+储存量也减少。在野生型CF-1株卵中使用米贝弗拉迪或匹莫齐特对Ca(V)3.2进行药理学抑制，可减少卵母细胞成熟过程中Ca2+的储存积累，并降低体外受精后Ca2+振荡的持久性、频率和数量。总的来说，这些数据表明Ca(V)3.2 t型通道在支持减数分裂成熟相关的ER Ca2+储存增加和介导发育激活所需的Ca2+内流方面具有以前未被认识到的作用。
Initiation of mouse embryonic development depends upon a series of fertilization-induced rises in intracellular Ca2+. Complete egg activation requires influx of extracellular Ca2+; however, the channels that mediate this influx remain unknown. Here, we tested whether the alpha 1 subunit of the T-type channel Ca(V)3.2, encoded by Cacna1h, mediates Ca2+ entry into oocytes. We show that mouse eggs express a robust voltage-activated Ca2+ current that is completely absent in Cacna1h(-/-) eggs. Cacna1h(-/-) females have reduced litter sizes, and careful analysis of Ca2+ oscillation patterns in Cacna1h(-/-) eggs following in vitro fertilization (IVF) revealed reductions in first transient length and oscillation persistence. Total and endoplasmic reticulum (ER) Ca2+ stores were also reduced in Cacna1h(-/-) eggs. Pharmacological inhibition of Ca(V)3.2 in wild-type CF-1 strain eggs using mibefradil or pimozide reduced Ca2+ store accumulation during oocyte maturation and reduced Ca2+ oscillation persistence, frequency and number following IVF. Overall, these data show that Ca(V)3.2 T-type channels have prev8iously unrecognized roles in supporting the meiotic-maturation-associated increase in ER Ca2+ stores and mediating Ca2+ influx required for the activation of development.