細(xì)胞核與染色體ppt課件-免費(fèi)閱讀
【正文】 The nucleolus Structure of the nucleolus Fibrillar centers FC Dense fibrillar ponent DFC Granular ponent Nucleolar associated chromatin Intranucleolar chromatin Perinucleolar chromatin Nucleolar matrix Fibrillar centers FC ? Exist rDNA, RNA polyE and ? Represent copy of NORs Dense fibrillar ponent DFC rRNA condensed in DFC Specificly bind with protein such as fibrillarin,nucleolin. Granular ponent Consist of RNP , digest by protease,and RNase ,pregranular of ribosome assembly Ribosome 70s(prok) 80s(euk) 30s 50s 60s 40s 16s 23s 5s 18s 28s 5s Nucleolus function rRNA transcription and machining exonuclease :核酸外切酶 The nucleolus is important for ribosome synthesis SRNA 28SrRNA 18 SRNA 5S rRNA 小亞基 沉降系數(shù) 40S 大亞基 60S 核仁外合成 蛋白質(zhì) 80S的核糖核蛋白顆粒 33種 蛋白質(zhì) 50種蛋白質(zhì) 核糖體 80S 45SrRNA Nucleolus in cell cycle （ nuclear matrix ） ? 或稱核骨架（ nucleoskeleton）為真核細(xì)胞核內(nèi)的網(wǎng)絡(luò)結(jié)構(gòu)，是指除核被膜、染色質(zhì)、核纖層及核仁以外的核內(nèi)網(wǎng)架體系。在幼蟲發(fā)育的某個(gè)階段，多線染色體的某些帶區(qū)疏松膨大，形成膨突（ puff），或巴氏環(huán)（ Balbiani ring）。 ? 對(duì)于更高級(jí)染色體包裝方式，至今尚不明確。 DNA first structure plexity ? 單一重復(fù) DNA ?code for genes and unique material ?% of unique genome is transcribed in frogs Moderately repetitive ? 4050% of genome is this type，調(diào)控基因表達(dá) ? Coding ? code for genes needed in large amounts ? rDNA to make rRNA (has 250 copies per human genome) Noncoding Coding SINES LINE ? 1015% ) ? 短片斷 ? GC 含量高 ? 位于著絲粒 ? 重復(fù)次數(shù) 100100,000 ? 功能未完全明確 Highly repetitive Minisatellite DNA(12100bp,3000 copy) Satellite DNA(5100bp) Microsatellite DNA(15bp form 5100bp) Chromatin protein Histone protein Sructure protein Nohistone protein : sequence specific DNA binding protein Nucleosome protein H2B,H2A,H3,H4, conservative H1,link functi
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