초록
본 연구의 목적은 넙치 인지질가수분해효소(PLC-${\delta}1$) 3가지 타입의 세포내 특성을 규명하고자 하였다. 일반적으로 인지질가수분해효소(PLC)의 신호전달경로는 핵, 세포막, 세포질에 분포한다고 알려져 있으나, 핵내 위치 메커니즘은 여전히 불분명하다. PoPLC-${\delta}1A$, PoPLC-${\delta}1B$ (Sf)과 PoPLC-${\delta}1B$ (Lf)의 3타입의 유전자들은 각각 핵위치 신호(NLS)와 핵방출서열(NES)을 포함하고 있다. 본 연구에서는, 넙치 3가지 타입 인지질가수분해효소(PLC-${\delta}1$)의 세포내 위치이동 메커니즘 분석을 위해 GFP 벡터에 유전자를 삽입하여 ionomycin과 thasogargin처리 후 세포위치와 이동양상을 공초점 레이저 주사현미경으로 관찰하였다. PoPLC-${\delta}1A$는 PoPLC-${\delta}1B$ (Lf)와 PoPLC-${\delta}1B$ (Sf)가 원형질막에 국한되어 분포할때 세포질과 세포막보다 세포 소기관에 분포되어 있었다. PoPLC-${\delta}1B$ (Lf) 및 PoPLC-${\delta}1$ (Sf)이 핵 세포질내 이동양상을 보이지 않을 때, PoPLC-${\delta}1A$은 ionomycin과 thapsigargin 처리에 의해 핵 내에 축적되는 양상을 나타냈다. 이런 결과는 손상되지 않은 기능적 NES 서열을 포함하는 PoPLC-${\delta}1A$가 어류에서 핵 세포질 내 왕복 및 이동의 주된 역할을 한다는 것을 보여주고 있다.
The purpose of this study was to investigate the cellular characterization of phospholipase C-${\delta}1$ in olive flounders (Paralichthys olivaceus). In general, phospholipase C signaling pathways are distributed in nuclei at plasma membranes and in cytoplasms, although the pathways' nuclear localization mechanisms are unclear. P. olivaceus duplicates type-A PoPLC-${\delta}1$ (PoPLC-${\delta}1A$), which has a high similarity to the human isoform PLC-${\delta}$; type-B PoPLC-${\delta}1$ (PoPLC-${\delta}1B$ [Sf]), which has a low similarity to the human isoform PLC-${\delta}$ and the alternative splice variant PoPLC-${\delta}1B$ (Lf), which has a nuclear localization signal (NLS) and a nuclear export signal (NES) for nuclear imports and exports, respectively. This study confirmed the effects of the cellular localization and translocation of GFP-tagged PoPLC-${\delta}1A$, PoPLC-${\delta}1B$ (Sf) and PoPLC-${\delta}1B$ (Lf). It administered treatments of $Ca^{2+}$ ionophore ionomycin and endoplasmic reticulum (ER)-$Ca^{2+}$ pump inhibitor thapsigargin to hirame natural-embryo (HINAE) cells. A laser-scanning confocal microscope was used. GFP-tagged PoPLC-${\delta}1A$ was distributed to the cellular organelles, rather than to the cytoplasms and cytomembranes, when PoPLC-${\delta}1B$ (Lf) and PoPLC-${\delta}1B$ (Sf) were localized at the plasma membranes. The treatments of ionomycin and thapsigargin showed the accumulation of PoPLC-${\delta}1A$ in the nuclei when PoPLC-${\delta}1B$ (Lf) nucleocytoplasmic shuttling and PoPLC-${\delta}1B$ (Sf) nucleocytoplasmic shuttling were not observed. The results were the first evidence that PoPLC-${\delta}1A$, which contains functional, intact NES sequences, has a main role in nucleocytoplasmic shuttling and translocation in fish.