Cofilin 1對斑馬魚胚原腸期細胞遷移影響之探討

Abstract

肌動蛋白去聚合蛋白(cofilin)為肌動蛋白去聚合因子(ADF/cofilin)的一種，能夠對肌動蛋白actin的聚合/去聚合進行調控，並且控制移動細胞中的偽足延伸。 為了探究cofilin在原腸期細胞遷移的功能，我們已從斑馬魚染色體組中分離出cofilin 1 (cfl1)；並且透過反轉錄酶-聚合酶鏈鎖反應(RT-PCR)與全標本原位雜交(WISH)得知，cfl1於早期胚胎發育中廣泛的表現在胚體的各部位。我們也已呈現過，針對cfl1的抑制，將造成包括在外包(epiboly)和集中與延伸(convergence and extension)時的細胞遷移產生缺陷。再者，我們透過細胞移植(cell transplantation)發現cfl1 MO(morpholino oligonucleotide)所產生的影響是細胞自主性的(cell- autonomous)。另外，進行內捲(involution)的偽足數量也會受到抑制cfl1的影響而有顯著地下降。我們更進一步透過穿透式電子顯微鏡與共軛交螢光顯微鏡的觀察，發現進行外包的包覆層(enveloping layer, EVL)與深細胞層(deep cell layer, DEL)在cfl1被抑制後，兩細胞層間的細胞附著變得鬆散。上述的實驗顯示，cfl1在斑馬原腸胚後期的細胞遷移過程中，扮演重要的角色。

Cofilins are members of actin-depolymerizing factor (ADF)/cofilin protein family that regulate actin treadmilling and the extension of pseudopods in motile cells. To study cofilin functions in gastrulation cell migration, we have isolated cofilin 1 (cfl1) from zebrafish genome, and its expression and functions have been examined. By RT-PCR and whole-mount in situ hybridization, cfl1 has been found to be ubiquitously expressed during early embryogenesis. We have also demonstrated that knockdown of cfl1 interfered cellular migration during epiboly, convergence and extension. Furthermore, the effects of cfl1 MO was found to be cell autonomous by transplantation experiments. In addition, pseudopods in the involuting cells were significantly reduced in the cfl1 morphants. The effects of cfl1 MO was further evident by the loose cell adhesions between enveloping layer (EVL) and deep cell layer (DEL) through transmission electronic microscopy and confocal microscopy. These results suggest that cfl1 participates in epiboly, involution, convergence and extension during zebrafish gastrulation.