在自然界中,某些動物天生就具有讓人驚嘆的再生能力,如蠑螈,如果斷了一條腿,不久以後便能長出一條新腿。斑馬魚也能夠在鰭斷開的位置重新長出新的鰭。
相比之下,人類卻只有最基本的再生能力。因此,科學家希望能通過對這些動物的研究,最終找到修復或再生受損組織的方法。
在一項發表於PNAS雜誌的研究報告中,密西根大學的研究人員利用模式生物斑馬魚發現,斑馬魚的不同組織的再生過程中,某些基因是相同的,如斑馬魚鰭的再生和心臟修復過程中的基因,在眼睛的光受體的再生中也發揮作用。這表明,不論身體的哪部分受損,其再生機制可能由一種共同的分子機制控制。
研究人員將斑馬魚置於強光下短暫處理,破壞斑馬魚眼睛中的光受體。這類似於人眼被太陽光灼傷,如果損傷較嚴重,往往會致人失明。但斑馬魚卻能很快長出新的神經元修復損傷。
那麼這些新形成的神經元是從什麼分化而來呢?研究人員猜測可能來自於視網膜的一種Müller glia細胞,這種猜測隨後在另一名研究人員的實驗中得到證實。
在這項新的研究中,研究人員Zhao Qin想找出促使Müller glia細胞再生原因。Qin仔細研究了斑馬魚受損並再生的視網膜中Müller glia細胞基因表達的模式,並以未受損的斑馬魚為對照。她發現兩組斑馬魚比較,一共有953個基因的表達模式發生變化,其中有兩個基因hspd1和mps1尤其值得關注,這兩個基因也參與到斑馬魚鰭的再生和心臟的再生。(生物谷Bioon.com)
生物谷推薦原始出處:
PNAS May 27, 2009, doi: 10.1073/pnas.0811186106
Genetic evidence for shared mechanisms of epimorphic regeneration in zebrafish
Zhao Qin, Linda K. Barthel and Pamela A. Raymond,1
1 Department of Molecular, Cellular, and Developmental Biology, University of Michigan College of Literature, Science, and the Arts, 830 North University, Ann Arbor, MI 48109-1048
In a microarray-based gene profiling analysis of Müller glia-derived retinal stem cells in light-damaged retinas from adult zebrafish, we found that 2 genes required for regeneration of fin and heart tissues in zebrafish, hspd1 (heat shock 60-kDa protein 1) and mps1 (monopolar spindle 1), were up-regulated. Expression of both genes in the neurogenic Müller glia and progenitors was independently verified by quantitative reverse transcriptase PCR and in situ hybridization. Functional analysis of temperature-sensitive mutants of hspd1 and mps1 revealed that both are necessary for Müller glia-based cone photoreceptor regeneration in adult zebrafish retina. In the amputated fin, hspd1 is required for the induction of mesenchymal stem cells and blastema formation, whereas mps1 is required at a later step for rapid cell proliferation and outgrowth. This temporal sequence of hspd1 and mps1 function is conserved in the regenerating retina. Comparison of gene expression profiles from regenerating zebrafish retina, caudal fin, and heart muscle revealed additional candidate genes potentially implicated in injury-induced epimorphic regeneration in diverse zebrafish tissues.