Lin-4

lin-4 microRNA precursor
	預測的lin-4二級結構和保守序列
識別符
代號	lin-4
Rfam	RF00052
miRBase	MI0000002
miRBase	MIPF0000303
	其他數據
RNA類型	Gene; miRNA
域	Eukaryota

lin-4是最早發現的microRNA，1993年由維克托·安布羅斯等人在模式生物秀麗隱桿線蟲的基因組中發現。 ^[1]^[2] 這是第一個被發現的miRNA，是一類參與基因調控的非編碼核糖核酸。^[3] miRNA轉錄形成70鹼基的前體後由Dicer酶切割形成21鹼基的產物^[4]。髮夾結構前體的範圍一般不為人所知，是根據髮夾結構預測來估計的。這些產物被認為通過與mRNA完全或部分互補而發揮調節作用。已發現lin-4基因位於一個單獨宿主基因的 4.11kb 內含子內（參見[1]）。

轉錄

lin-4由自主miRNA啟動子轉錄，並受發育調控，lin-4 miRNA積累發生在胚胎後發育的L2階段。此外，在lin-4成熟形式出現時，內源性lin-4 初級轉錄本也會上調。^[5] lin-4位於秀麗隱杆線蟲的II號染色體上，與lin-14（英語：lin-14） mRNA 的3' 非轉譯區 (UTR)中的序列互補，該互補轉錄本含有7個結合位點以及9個核苷酸核心元素CUCAGGGAA。lin-4:lin-14雙鏈體呈現出一種不尋常的扭結結構，這是由於鹼基對不匹配導致凹槽尺寸和鹼基堆積發生變化所致。^[5] 該lin-4:lin-14對與秀麗隱杆線蟲中的IGF-1通路有關，與其發育的改變有關。^[6]

發育影響

lin-4決定線蟲幼蟲發育事件的開始。

參考文獻

^ Lee RC, Feinbaum RL, Ambros V. The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14.. Cell. 1993, 75 (5): 843–854. PMID 8252621. doi:10.1016/0092-8674(93)90529-Y  .
^ Rougvie, AE. Control of developmental timing in animals. Nat Rev Genet. 2001, 2 (9): 690–701. PMID 11533718. doi:10.1038/35088566.
^ Ambros, V. microRNAs: tiny regulators with great potential. Cell. 2001, 107 (7): 823–826. PMID 11779458. doi:10.1016/S0092-8674(01)00616-X  .
^ Rougvie, AE. Control of developmental timing in animals. Nat Rev Genet. 2001, 2 (9): 690–701. PMID 11533718. doi:10.1038/35088566.
^ ^5.0 ^5.1 Balasubramanian C, Ojha RP, Maiti S, Desideri A. Sampling the structure of the noncanonical lin-4:lin-14 microRNA:mRNA complex by molecular dynamics simulations.. J Phys Chem B. 2010, 114 (49): 16443–9. PMID 21090710. doi:10.1021/jp104193r.
^ Boehm M, Slack F. A developmental timing microRNA and its target regulate life span in C. elegans.. Science. 2005, 310 (5756): 1954–7. PMID 16373574. doi:10.1126/science.1115596.

外部連結

[pmid8252621-1] Lee RC, Feinbaum RL, Ambros V. The C. elegans heterochronic gene lin-4 encodes small RNAs with antisense complementarity to lin-14.. Cell. 1993, 75 (5): 843–854. PMID 8252621. doi:10.1016/0092-8674(93)90529-Y  .

[2] Rougvie, AE. Control of developmental timing in animals. Nat Rev Genet. 2001, 2 (9): 690–701. PMID 11533718. doi:10.1038/35088566.

[3] Ambros, V. microRNAs: tiny regulators with great potential. Cell. 2001, 107 (7): 823–826. PMID 11779458. doi:10.1016/S0092-8674(01)00616-X  .

[4] Rougvie, AE. Control of developmental timing in animals. Nat Rev Genet. 2001, 2 (9): 690–701. PMID 11533718. doi:10.1038/35088566.

[pmid21090710-5] 5.0 ^5.1 Balasubramanian C, Ojha RP, Maiti S, Desideri A. Sampling the structure of the noncanonical lin-4:lin-14 microRNA:mRNA complex by molecular dynamics simulations.. J Phys Chem B. 2010, 114 (49): 16443–9. PMID 21090710. doi:10.1021/jp104193r.

[pmid16373574-6] Boehm M, Slack F. A developmental timing microRNA and its target regulate life span in C. elegans.. Science. 2005, 310 (5756): 1954–7. PMID 16373574. doi:10.1126/science.1115596.

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