美国国家标准技术研究院（NIST）和盖提斯堡学院（Gettysburg College）的研究人员近日通过研究成功实现了单一细胞中线粒体的提取。这项研究将有助于科学家更好地针对特定线粒体进行深入研究，从而了解各种遗传疾病的产生机制。研究报告发表在近期《公共科学图书馆—综合》（PLoS One）上。
人体细胞中线粒体的提取是一段复杂的过程。NIST的研究人员开发出的这套技术犹如外科手术般地可将细胞中的这种微小“引擎”剥离出来，为研究线粒体DNA与相应疾病的关联提供了潜在帮助。（图片来源：NIST）
在这项研究中，研究小组采用了一种先前用于提取独立稻米细胞中单一染色体的方法。他们利用激光将细胞外膜切开一个小口，然后使用另一束激光，像“钳子”一般将线粒体与周围的物质分离开，最后，他们用一种末端不足1微米大小的微小吸管将线粒体提取出来。
这种提取方法让研究小组能将单个线粒体置入小试管中，并采用传统方法对其遗传构成进行仔细研究。他们发现整个细胞的变异过程都能在单一线粒体中得到体现，这意味着对线粒体疾病的广泛性遗传研究或将最终成为可能。
“用‘钳子’获取这样微小的物质并不是件容易的事”，参与研究的Koren Deckman说，“但依赖于NIST十多年的研究工作，我们现在已找到方法对线粒体进行提取并观察其整个转录过程，这也意味着我们能保证，可从特定细胞中获得（你想要的）线粒体样本。这对医学研究人员了解遗传疾病将有很大帮助”。（生物谷Bioon.com）
生物谷推荐原文出处：
PLoS ONE 5(12): e14359. doi:10.1371/journal.pone.0014359
Detection of Heteroplasmic Mitochondrial DNA in Single Mitochondria
Joseph E. Reiner1*, Rani B. Kishore1, Barbara C. Levin2, Thomas Albanetti3, Nicholas Boire3, Ashley Knipe3, Kristian Helmerson1, Koren Holland Deckman3
1 Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America, 2 Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States of America, 3 Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania, United States of America
Abstract
Background
Mitochondrial DNA (mtDNA) genome mutations can lead to energy and respiratory-related disorders like myoclonic epilepsy with ragged red fiber disease (MERRF), mitochondrial myopathy, encephalopathy, lactic acidosis and stroke (MELAS) syndrome, and Leber's hereditary optic neuropathy (LHON). It is not well understood what effect the distribution of mutated mtDNA throughout the mitochondrial matrix has on the development of mitochondrial-based disorders. Insight into this complex sub-cellular heterogeneity may further our understanding of the development of mitochondria-related diseases.
Methodology
This work describes a method for isolating individual mitochondria from single cells and performing molecular analysis on that single mitochondrion's DNA. An optical tweezer extracts a single mitochondrion from a lysed human HL-60 cell. Then a micron-sized femtopipette tip captures the mitochondrion for subsequent analysis. Multiple rounds of conventional DNA amplification and standard sequencing methods enable the detection of a heteroplasmic mixture in the mtDNA from a single mitochondrion.
Significance
Molecular analysis of mtDNA from the individually extracted mitochondrion demonstrates that a heteroplasmy is present in single mitochondria at various ratios consistent with the 50/50 heteroplasmy ratio found in single cells that contain multiple mitochondria.
