Klein Cornelia, Terrao Monica, Clayton Christine
Centre for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, Heidelberg, Germany.
PLoS One. 2017 May 17;12(5):e0177901. doi: 10.1371/journal.pone.0177901. eCollection 2017.
Kinetoplastids rely heavily on post-transcriptional mechanisms for control of gene expression, with regulation of mRNA processing, translation and degradation by RNA-binding proteins. ZC3H32 is a cytosolic mRNA-binding protein with three non-canonical CCCH zinc finger domains. It is much more abundant in bloodstream-form Trypanosoma brucei than in procyclic forms. Tethering of ZC3H32 to a reporter mRNA suppressed translation and resulted in mRNA degradation, and deletion analysis suggested that this activity was present in both the N- and C-terminal domains, but not the central zinc finger-containing domain. Tandem affinity purification, however, revealed no interaction partners that might account for this activity. RNASeq analyses did not yield any evidence for sequence-specific binding or regulation of specific mRNAs. The presence of ZC3H32 homologues in monogenetic and free-living Euglenids also argues against a role in developmental regulation, although its function may have diverged in evolution. T. brucei ZC3H32 might be implicated in basal mRNA metabolism, with this role perhaps being taken over by another protein in procyclic forms.
动质体在很大程度上依赖转录后机制来控制基因表达，通过RNA结合蛋白对mRNA加工、翻译和降解进行调控。ZC3H32是一种具有三个非典型CCCH锌指结构域的胞质mRNA结合蛋白。它在布氏锥虫的血流形式中比在原循环形式中丰富得多。将ZC3H32与报告mRNA拴系会抑制翻译并导致mRNA降解，缺失分析表明这种活性存在于N端和C端结构域，但不存在于含中央锌指的结构域。然而，串联亲和纯化未发现可能解释这种活性的相互作用伙伴。RNA测序分析未产生任何序列特异性结合或特定mRNA调控的证据。单基因和自由生活的眼虫中存在ZC3H32同源物，这也反驳了其在发育调控中的作用，尽管其功能在进化过程中可能已经发生了分化。布氏锥虫ZC3H32可能参与基础mRNA代谢，在原循环形式中这一作用可能由另一种蛋白质承担。
