ImprintedRNA的应用.ppt

Imprinted RNA的应用 2010.11.11 X inactivation, the process whereby one of the two X chromosomes is inactivated in female mammals so that both males and females have an equal dosage of X-linked genes. Two noncoding RNAs:Xist and its antisense partner Tsix Xist shows imprinted expression in the early embryo, being repressed on the maternally derived active X Chr (Xm) but expressed from the paternally derived inactive X Chr (Xp) X-Chromosome Inactivation and Skin Disease The inactivated X chromosome Molecular mechanism of XCI Skewed and Incomplete X-inactivation In primary nonrandom X-inactivation, some factor or modification alters the random choice. if one X contains a gene or genes that confer a growth advantage or disadvantage From a clinical standpoint, skewed X-inactivation can affect females who are heterozygous for X-linked gene mutations. ‘‘all-or-none’’ molecular nature of X-inactivation, ~50% of cells producing only the mutant X-linked gene product and ~50% of cells producing only the wild-type product although ‘‘escape’’ can occur. half of the cells of X-linked heterozygotes express only the mutant gene. female heterozygotes hemizygous males Indicated the cells expressing the wild-type gene can provide protection against the disease. Blaschko线 在躯干背部跨脊柱皮面呈Ⅴ形,在躯干前、侧部皮面呈S形,四肢皮面呈垂直条纹,腹部皮面呈涡轮状,头皮呈螺旋状. 与皮肤的形成有关,反映早期胚胎发育过程中皮肤的胚层发育正常.Blaschko线在正常体表并不显现.但以Blaschko线表现的皮肤病则很多,如色素失禁、线状表皮痣、线状苔藓等. Alfred Blaschko于1901年首次描述. incontinentia pigmenti(色素失调症) X-linked NF-kB essential modulator (NEMO) gene the relative ratios of mutant-to-normal X chromosome inactivation would correlate to the severity of disease. secondary nonrandom X-inactivation can occur. Anhidrotic ectodermal dysplasia(外胚层发育异常无汗症) X-linked ectodysplasin A (EDA) gene oral–facial–digital syndrome type 1(口面指综合症Ⅰ) Affected girls have spirals of hairlessness on the scalp ncRNAimprint /ncRNAimprint/down.php