γ-Tubulin complex protein 4 (GCP4, encoded by AT3G53760) participates in microtubule (MT) nucleation in Arabidopsis thaliana, affecting the MT nucleation angles in cortical MTs, and the formation of the spindle and phragmoplasts during mitosis. Here, we report that GCP4 plays a critical role in gametophyte development. The results indicate that the gcp4 mutant caused by T-DNA insertion may express an aberrant gene product interfering with normal GCP4 expression, ultimately leading to the formation of desiccated ovules and aborted seeds. An analysis of transmission efficiency (TE) indicated that female gametophytes were more impaired in development than male gametophytes, and so observation and analysis of gametophyte defects were conducted. Complementation lines obtained by the native promoter and GCP4-coded CDS gene sequence fused with GFP reduced the numbers of lethal phenotypes of the gcp4 mutant. The localization of GCP4 in the gametophyte was detected in cytoplasm around nuclei and in vicinity of plasma membrane of pollen grains, and also detected in full cytoplasm and around the nuclei of ovules in complementation line. Thus, it was established that GCP4 influences the functionality of gametophytes during gametophyte development.

中文翻译：

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GCP4蛋白对拟南芥配子体发育的影响

γ-微管蛋白复合蛋白 4（GCP4，由 AT3G53760 编码）参与拟南芥中的微管 (MT) 成核，影响皮质 MT 中的 MT 成核角度，以及有丝分裂过程中纺锤体和成膜体的形成。在这里，我们报告 GCP4 在配子体发育中起着关键作用。结果表明，由T-DNA插入引起的gcp4突变体可能表达干扰GCP4正常表达的异常基因产物，最终导致胚珠干燥和种子流产。传递效率（TE）分析表明，雌配子体的发育比雄配子体更受损，因此对配子体缺陷进行了观察和分析。通过与 GFP 融合的天然启动子和 GCP4 编码的 CDS 基因序列获得的互补品系减少了 gcp4 突变体的致死表型数量。GCP4在配子体中的定位在花粉粒细胞核周围和质膜附近的细胞质中检测到，在互补系中的完整细胞质和胚珠细胞核周围也检测到。因此，确定 GCP4 在配子体发育过程中影响配子体的功能。