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Death comes in small packages [复制链接]

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楼主
发表于 2009-3-6 08:16 |只看该作者 |倒序浏览 |打印
McKay/NAS
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Killer sunburns are detected by the smallest of genes, according to Bruce McKay and colleagues (Ottawa Regional Cancer Centre, Ottawa, ON). A bias toward damage of larger genes leaves intact only the tiny genes, which make sure that overdamaged cells die.
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UV rays create DNA lesions that block RNA polymerases. A little damage can be cleaned up by UV-induced repair pathways that remove the lesions. But too much UV—which may make more lesions than can be repaired—triggers apoptosis instead. McKay now shows that the small size of apoptotic genes means that they rule when UV levels are high.- p# J% v; E* Z% `3 |. U# c
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The authors find that fewer genes are transcribed as UV levels increase, and those that are transcribed are smaller, with fewer and shorter introns. These small genes include many known mitochondrial apoptotic genes, which were activated at the highest UV dose tested. Genes encoding repair proteins or survival proteins, such as Bcl-XL, were induced only at low UV levels, probably because they are larger and more likely to suffer from transcription-blocking lesions.9 P' U! n& ?$ z& g: Z" w( \
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"The shift in the pattern of gene expression is the result of a passive mechanism," says McKay. So no extra energy is needed to convince highly injured cells to die.
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McKay, B., et al. 2004. Proc. Natl. Acad. Sci. USA. 10.1073/pnas.0308181101.(The transcription of survival genes (whi)

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沙发
发表于 2015-6-3 15:27 |只看该作者
顶的就是你  

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藤椅
发表于 2015-6-17 17:29 |只看该作者
一个有信念者所开发出的力量,大于99个只有兴趣者。  

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板凳
发表于 2015-6-30 09:18 |只看该作者
干细胞之家微信公众号
今天无聊来逛逛  

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报纸
发表于 2015-7-10 10:54 |只看该作者
脂肪干细胞

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地板
发表于 2015-8-7 20:33 |只看该作者
加油啊!偶一定会追随你左右,偶坚定此贴必然会起到抛砖引玉的作用~  

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发表于 2015-8-10 22:22 |只看该作者
琴棋书画不会,洗衣做饭嫌累。  

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发表于 2015-9-24 21:00 |只看该作者
肿瘤干细胞

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发表于 2015-10-10 18:06 |只看该作者
呵呵,明白了  

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发表于 2015-10-25 11:10 |只看该作者
努力~~各位。。。  
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