Non-mendelian inheritance of paralogs of 2 cytoskeletal genes in the ciliate Chilodonella uncinata
Non-mendelian inheritance of paralogs of 2 cytoskeletal genes in the ciliate Chilodonella uncinata
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DOI：
10.1093/molbev/msm203
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发表时间：
2007-11-01
影响因子：
10.7
通讯作者：
Katz, L. A.
中科院分区：
文献类型：
--
作者：
Robinson, T.;Katz, L. A.
对非孟德尔遗传作用的认识正在上升，特别是因为表观遗传现象被证明可以塑造基因组转化为表型。纤毛虫为探索表观遗传学的作用提供了一个模型系统，因为纤毛虫的每个细胞中都有生殖系（微核）和体细胞（大核）基因组。在纤毛虫Chilodonella uncinata中，大核被广泛地片段化，使得许多基因最终位于它们自己的染色体上。因此，有可能跟踪C大核内未连锁基因的命运。钩状的在这里，我们证明了C。uncinata是复杂的，涉及孟德尔传递微核和大核和表观遗传现象。2株C. uncinata及其后代共享相同的rDNA基因座和2个相同的β-微管蛋白旁系同源物，但具有不同的肌动蛋白旁系同源物和一些不共享的β-微管蛋白旁系同源物。我们提出了一个模型，其中所有的分歧旁系同源物都存在于纤毛虫微核。在这种模式下，不同的旁系同源物在接合后保留在发育中的大核中。我们进一步推测，表观遗传机制，如RNA干扰，参与选择性保留特定的旁系同源物线内。该系统允许探索形成体细胞基因组的表观遗传现象，并提供与动物体内体细胞核发育研究的相似之处。
Recognition of the role of non-Mendelian inheritance is on the rise, particularly as epigenetic phenomena are shown to shape the transformation of genomes into phenotypes. Ciliates provide a model system in which to explore the role of epigenetics because ciliates have both a germ line (micronuclear) and somatic (macronuclear) genome within every cell. In the ciliate Chilodonella uncinata, the macronucleus is extensively fragmented such that many genes end up on their own chromosomes. Hence, it is possible to track the fate of unlinked genes within macronuclei of C. uncinata. Here we demonstrate that the pattern of inheritance in isolates of C. uncinata is complex and involves both Mendelian transmission between micronuclei and macronuclei and epigenetic phenomena. The macronuclei from 2 isolates of C. uncinata and their progeny share identical rDNA loci and 2 identical beta-tubulin paralogs, yet have different actin paralogs and some beta-tubulin paralogs that are not shared. We propose a model in which all the divergent paralogs are present in the ciliate micronuclei. Under this model, different paralogs are retained in developing macronuclei following conjugation. We further speculate that an epigenetic mechanism, such as RNA interference, is involved in selective retention of specific paralogs within lines. This system allows the exploration of epigenetic phenomena that shape somatic genomes and provides parallels to studies of the development of somatic nuclei within animals.