Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076 Tübingen, Germany.
Department for Integrative Evolutionary Biology, Max Planck Institute for Developmental Biology, Max-Planck-Ring 9, 72076 Tübingen, Germany.
Cell Rep. 2018 Jun 5;23(10):2835-2843.e4. doi: 10.1016/j.celrep.2018.05.008.
Switching between alternative complex phenotypes is often regulated by "supergenes," polymorphic clusters of linked genes such as in butterfly mimicry. In contrast, phenotypic plasticity results in alternative complex phenotypes controlled by environmental influences rather than polymorphisms. Here, we show that the developmental switch gene regulating predatory versus non-predatory mouth-form plasticity in the nematode Pristionchus pacificus is part of a multi-gene locus containing two sulfatases and two α-N-acetylglucosaminidases (nag). We provide functional characterization of all four genes, using CRISPR-Cas9-based reverse genetics, and show that nag genes and the previously identified eud-1/sulfatase have opposing influences. Members of the multi-gene locus show non-overlapping neuronal expression and epistatic relationships. The locus architecture is conserved in the entire genus Pristionchus. Interestingly, divergence between paralogs is counteracted by gene conversion, as inferred from phylogenies and genotypes of CRISPR-Cas9-induced mutants. Thus, we found that physical linkage accompanies regulatory linkage between switch genes controlling plasticity in P. pacificus.
在蝴蝶拟态等情况下，不同复杂表型之间的转换通常受“超级基因”（即多个连锁基因的多态性簇）调控。相比之下，表型可塑性导致的不同复杂表型由环境影响而非多态性控制。在这里，我们发现调控线虫 Pristionchus pacificus 捕食性与非捕食性口型可塑性的发育开关基因是包含两个硫酸酯酶和两个α-N-乙酰氨基葡萄糖苷酶（nag）的多基因座的一部分。我们使用基于 CRISPR-Cas9 的反向遗传学对所有四个基因进行了功能表征，并表明 nag 基因和之前鉴定的 eud-1/硫酸酯酶具有相反的影响。多基因座的成员表现出非重叠的神经元表达和上位性关系。该基因座结构在整个 Pristionchus 属中是保守的。有趣的是，从 CRISPR-Cas9 诱导突变体的系统发育和基因型推断，旁系同源物之间的分歧被基因转换抵消了。因此，我们发现控制 P. pacificus 可塑性的开关基因之间的物理连锁伴随着调控连锁。
