近日,，一篇發(fā)表在《美國(guó)國(guó)家科學(xué)院院刊》（Proceedings of the National Academy of Sciences）上的研究稱,，通過(guò)研制人造人類染色體（HAC）修復(fù)人類細(xì)胞基因缺陷的實(shí)驗(yàn)取得了良好的效果。
與基因治療中采用的病毒載體相比,，HAC可以避免其無(wú)法控制基因拷貝數(shù)目,，以及基因突變和基因沉默等缺點(diǎn)。
研究者通過(guò)使用相互結(jié)合的2個(gè)人造染色體來(lái)具有基因缺陷的人類細(xì)胞,，該細(xì)胞從有腫瘤相關(guān)基因缺陷患者身上分離而來(lái),。首先，他們將該腫瘤相關(guān)基因從患者的基因組DNA中分離出來(lái),，然后使HAC攜帶該基因,，再將HAC導(dǎo)入該細(xì)胞進(jìn)行修復(fù)。他們觀察到嵌入的腫瘤相關(guān)基因能在該細(xì)胞中正常表達(dá)蛋白質(zhì)并修復(fù)該細(xì)胞的缺陷,。
隨后,，研究者又找出了能使該人造染色體失活的方法。表明這種方法可以用來(lái)研究HAC介導(dǎo)的細(xì)胞治療,。
HAC穩(wěn)定性較高,，且能可逆性地將完整基因?qū)肴祟惣?xì)胞，有望在基因功能研究和臨床基因治療研究等方面發(fā)揮重要作用,。（生物谷bioon.com）
doi:10.1073/pnas.1114483108
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Human artificial chromosome (HAC) vector with a conditional centromere for correction of genetic deficiencies in human cells
Jung-Hyun Kim, Artem Kononenko, Indri Erliandri, Tae-Aug Kim,Megumi Nakano, Yuichi Iida, J. Carl Barrett, Mitsuo Oshimura,Hiroshi Masumoto, William C. Earnshaw, Vladimir Larionov, andNatalay Kouprina.
Human artificial chromosome (HAC)-based vectors offer a promising system for delivery and expression of full-length human genes of any size. HACs avoid the limited cloning capacity, lack of copy number control, and insertional mutagenesis caused by integration into host chromosomes that plague viral vectors. We previously described a synthetic HAC that can be easily eliminated from cell populations by inactivation of its conditional kinetochore. Here, we demonstrate the utility of this HAC, which has a unique gene acceptor site, for delivery of full-length genes and correction of genetic deficiencies in human cells. A battery of functional tests was performed to demonstrate expression ofNBS1 and VHL genes from the HAC at physiological levels. We also show that phenotypes arising from stable gene expression can be reversed when cells are "cured" of the HAC by inactivating its kinetochore in proliferating cell populations, a feature that provides a control for phenotypic changes attributed to expression of HAC-encoded genes. This generation of human artificial chromosomes should be suitable for studies of gene function and therapeutic applications.
