Stem Cell Program, Division of Dermatology, Department of Medicine, Institute for Genomic Medicine, University of California San Diego, San Diego, California, United States of America.
PLoS One. 2011;6(11):e27603. doi: 10.1371/journal.pone.0027603. Epub 2011 Nov 16.
The hair of all mammals consists of terminally differentiated cells that undergo a specialized form of apoptosis called cornification. While DNA is destroyed during cornification, the extent to which RNA is lost is unknown. Here we find that multiple types of RNA are incompletely degraded after hair shaft formation in both mouse and human. Notably, mRNAs and short regulatory microRNAs (miRNAs) are stable in the hair as far as 10 cm from the scalp. To better characterize the post-apoptotic RNAs that escape degradation in the hair, we performed sequencing (RNA-seq) on RNA isolated from hair shafts pooled from several individuals. This hair shaft RNA library, which encompasses different hair types, genders, and populations, revealed 7,193 mRNAs, 449 miRNAs and thousands of unannotated transcripts that remain in the post-apoptotic hair. A comparison of the hair shaft RNA library to that of viable keratinocytes revealed surprisingly similar patterns of gene coverage and indicates that degradation of RNA is highly inefficient during apoptosis of hair lineages. The generation of a hair shaft RNA library could be used as months of accumulated transcriptional history useful for retrospective detection of disease, drug response and environmental exposure.
所有哺乳动物的毛发都由终末分化的细胞组成，这些细胞经历一种称为角质化的特殊形式的细胞凋亡。虽然在角质化过程中 DNA 被破坏，但 RNA 的丢失程度尚不清楚。在这里，我们发现，在小鼠和人类的毛干形成后，多种类型的 RNA 并未完全降解。值得注意的是，mRNA 和短的调控 microRNA（miRNA）在距离头皮 10 厘米远的毛发中仍然稳定。为了更好地表征在毛发中逃避降解的凋亡后 RNA，我们对从几个人的毛干中分离的 RNA 进行了测序（RNA-seq）。这个涵盖不同毛发类型、性别和人群的毛干 RNA 文库，揭示了 7193 个 mRNA、449 个 miRNA 和数千个未注释的转录本，它们仍然存在于凋亡后的毛发中。将毛干 RNA 文库与有活力的角蛋白细胞进行比较，发现基因覆盖的模式惊人地相似，这表明在毛发谱系的细胞凋亡过程中，RNA 的降解效率非常低。生成一个毛干 RNA 文库可以作为数月累积的转录历史，用于回溯性检测疾病、药物反应和环境暴露。
