PDF(Pubmed)
Abstract：
Contrary to dogma, evolutionarily young and dynamic genes can encode essential functions. We find that evolutionarily dynamic ZAD-ZNF genes, which encode the most abundant class of insect transcription factors, are more likely to encode essential functions in Drosophila melanogaster than ancient, conserved ZAD-ZNF genes. We focus on the Nicknack ZAD-ZNF gene, which is evolutionarily young, poorly retained in Drosophila species, and evolves under strong positive selection. Yet we find that it is necessary for larval development in D. melanogaster. We show that Nicknack encodes a heterochromatin-localizing protein like its paralog Oddjob, also an evolutionarily dynamic yet essential ZAD-ZNF gene. We find that the divergent D. simulans Nicknack protein can still localize to D. melanogaster heterochromatin and rescue viability of female but not male Nicknack-null D. melanogaster. Our findings suggest that innovation for rapidly changing heterochromatin functions might generally explain the essentiality of many evolutionarily dynamic ZAD-ZNF genes in insects.
摘要：
与教条相反，进化上年轻和动态的基因可以编码必要的功能。我们发现进化动态的ZAD-ZNF基因，编码最丰富的昆虫转录因子，比古代更有可能编码黑腹果蝇的基本功能，保守的ZAD-ZNF基因。我们专注于NicknackZAD-ZNF基因，进化上很年轻，在果蝇物种中保留较差，并在强大的正向选择下进化。然而，我们发现黑腹D.melanogaster的幼虫发育是必要的。我们证明Nicknack编码异染色质定位蛋白，就像它的旁白Oddjob一样，也是进化动态但必不可少的ZAD-ZNF基因。我们发现，不同的D.simulansNicknack蛋白仍然可以定位于D.melanogaster异染色质，并挽救雌性而不是雄性Nicknack-nullD.melanogaster的生存能力。我们的发现表明，快速变化的异染色质功能的创新可能通常可以解释昆虫中许多进化动态ZAD-ZNF基因的重要性。
