論文宣讀

 隱花色素(Cryptochromes, Cry)為細胞內晝夜節律調控機制的分子之一，最初被歸類為類光裂解酶藍光受體，在擬南芥(Arabidopsis)被中發現並扮演著調節生長的角色，後來也在其他植物、微生物、動物中被發現。第四型隱花色素(Cryptochromes4, Cry4)目前只有在鳥禽、斑馬魚等非哺乳脊椎動動物中發現，但目前其功能尚不甚了解。Cry家族成員具光裂解酶同源區與FAD輔因子，被發現廣泛存在於各物種之光感受器。文獻指出，二型Cry與Cry4皆廣泛的表現在家禽各組織中，不同於二型Cry，Cry4的表現並不受到光所誘導，然 Cry4 具有光依性結構變化(light-dependent conformational change)的特性，目前普遍認為Cry4為中樞晝夜節律(circadian rhythm)系統中的光受體(photoreceptors)，或扮演候鳥遷徙時磁感應受體(magnetoreceptor)，然其在周邊組織的角色未有任何報導。本次試驗以蛋雞顆粒細胞(granulosa cells)與濾泡膜(theca cells)細胞作為模型探討Cry4在周邊組織的角色功能，首先確認細胞是否表現Cry4，結果顯示F1-F5濾泡、小黃濾泡(small yellow follicle, SYF)、大白濾泡(large withe follicle, LWF)皆表現Cry4。前人的研究顯示，內源性LH會誘導蛋雞第二型Cry的基因表現，但是否影響Cry4蛋白表現則未知。以蛋雞下蛋後1、11、21小時為採樣時間，其中21小時為蛋雞開始大量分泌黃體成長激素(Luteinizing hormone, LH)，收集F1-F5濾泡、SYF、LWF，並以肝臟、下視丘為陰性對照組。結果顯示F1-F5濾泡沒有明顯變化趨勢，SYF、LWF則出現了明顯的變化趨勢，且兩者的變化不盡相同，肝臟則如預期沒有變化趨勢，下視丘則受到LH的誘導，第21小時的變化為先前時間點的5倍。以上結果表是內源性 LH surge 會調控誘導蛋雞濾泡細胞中 Cry4 蛋白的表達，但關於 Cry4 在濾泡發育的具體作用還需要進一步研究。
 
關鍵字:晝夜節律、隱花色素4、濾泡發育、排卵、雞

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