2019-04-222024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/653859摘要：表皮作為協助動物生存的重要保護屏障，同時也影響免疫、分泌、感知和癒傷等功能。在秀麗隱桿線蟲(C. elegans)，表皮主要由兩種皮膜細胞組成，包括接縫細胞(seam cell)與hyp7合胞體(syncytium)。利用具綠色螢光的AJM-1和HMR-1融合蛋白，在野生型線蟲成蟲可觀察到接縫合胞體具有兩條平行的細胞邊界。我們發現轉錄因子基因blmp-1(哺乳類BLIMP-1/PRDI-BF1同源基因)的功能缺失，會導致成蟲的黏連結合蛋白排列發生異常。這代表blmp-1參與維持成蟲接縫細胞的頂層形態。為測試BLMP-1是否具轉錄因子功能以控制接縫細胞頂層形態，我們用野生型與blmp-1突變株進行RNA-sequencing分析。結果顯示blmp-1突變株成蟲中某些專屬於蛻皮的基因轉錄量升高。因此blmp-1可能是透過避免蛻皮基因的錯誤表現來調控成蟲表皮命運，如角質層形成。從blmp-1突變株中篩選表現量提高的候選基因和分析BLMP-1共通結合序列，我們發現參與N-連結醣基化的甘露糖轉移&#37238;基因bus-8，與分泌型的蛻皮訊息醣蛋白基因mlt-8，當被減弱功能時可顯著抑制blmp-1突變株的接縫細胞頂層形態異常。在接縫合胞體或hyp7大量表現bus-8和mlt-8基因便足以造成接縫細胞頂層形態異常。我們的實驗結果顯示blmp-1作為異時基因控制成蟲表皮命運和角質層完整性，避免蛻皮的特定基因在成蟲錯誤表現。本計畫將進一步建立BLMP-1如何整合基因表現、醣基化和蛋白質運輸以維繫表皮細胞頂層型態的作用機制。<br> Abstract: Epidermis is a protective barrier important for animal survival, and also functions in immunity, secretion, sensation and wound repair. In the nematode Caenorhabditis elegans, epidermis is mainly composed of two types of epithelial cells, seam cells and hyp7. Using GFP-labeled AJM-1 and HMR-1 fusion proteins as reporters, two parallel boundaries outlined the seam syncytium were observed in the wild-type adult, while the loss of blmp-1, which encodes a zinc finger transcription factor similar to mammalian BLIMP-1/PRDI-BF1, caused a disorganized localization pattern of the adherens junction proteins at the adult stage. These results indicated that blmp-1 functions in the maintenance of seam apical morphology in adults. We performed an RNA-sequencing analysis of wild-type and blmp-1 mutant worms. Our data showed that several genes expressed specifically in epidermis during molt had higher transcript levels in the blmp-1 mutants than the wild-type at the adult stage. Thus, blmp-1 likely regulates the adult epidermal fate, at least in cuticle formation, by preventing inappropriate expression of molting genes. We found that bus-8 and mlt-8, encoding a mannosyltransferase in N-linked glycosylation and a secreted molting signal glycoprotein, when knockdowned, significantly suppressed the abnormal apical seam cell morphology of blmp-1 mutants. Overexpression of bus-8 or mlt-8, in either seam or hyp7 syncytium was sufficient to cause the apical seam morphology defect. Our data support a model that blmp-1 functions as a heterochronic gene to control the adult epidermal fate and cuticle integrity by preventing mis-expression of molt-specific gene in adults. This proposal aims to understand how BLMP-1 integrates gene expression, glycosylation, and protein trafficking in the maintenance of apical epidermal cell morphology.BLIMP-1BLIMP-1