Khaitovich Philipp, Kelso Janet, Franz Henriette, Visagie Johann, Giger Thomas, Joerchel Sabrina, Petzold Ekkehard, Green Richard E, Lachmann Michael, Pääbo Svante
Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
PLoS Genet. 2006 Oct 13;2(10):e171. doi: 10.1371/journal.pgen.0020171. Epub 2006 Aug 28.
Although a large proportion of human transcription occurs outside the boundaries of known genes, the functional significance of this transcription remains unknown. We have compared the expression patterns of known genes as well as intergenic transcripts within the ENCODE regions between humans and chimpanzees in brain, heart, testis, and lymphoblastoid cell lines. We find that intergenic transcripts show patterns of tissue-specific conservation of their expression, which are comparable to exonic transcripts of known genes. This suggests that intergenic transcripts are subject to functional constraints that restrict their rate of evolutionary change as well as putative positive selection to an extent comparable to that of classical protein-coding genes. In brain and testis, we find that part of this intergenic transcription is caused by widespread use of alternative promoters. Further, we find that about half of the expression differences between humans and chimpanzees are due to intergenic transcripts.
尽管很大一部分人类转录发生在已知基因的边界之外，但这种转录的功能意义仍然未知。我们比较了人类和黑猩猩在大脑、心脏、睾丸以及淋巴母细胞系的ENCODE区域内已知基因和基因间转录本的表达模式。我们发现基因间转录本显示出其表达的组织特异性保守模式，这与已知基因的外显子转录本相当。这表明基因间转录本受到功能限制，这些限制将它们的进化变化速率以及假定的正选择限制在与经典蛋白质编码基因相当的程度。在大脑和睾丸中，我们发现这种基因间转录的一部分是由广泛使用替代启动子引起的。此外，我们发现人类和黑猩猩之间约一半的表达差异是由于基因间转录本造成的。
