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Complementarity to an mi RNA seed region is sufficient to induce moderate repression of a target transcript in the unicellular green alga Chlamydomonas reinhardtii
Author(s) -
Yamasaki Tomohito,
Voshall Adam,
Kim EunJeong,
Moriyama Etsuko,
Cerutti Heriberto,
Ohama Takeshi
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12354
Subject(s) - chlamydomonas reinhardtii , biology , gene silencing , psychological repression , chlamydomonas , microbiology and biotechnology , argonaute , microrna , rna , multicellular organism , genetics , gene expression , rna interference , gene , mutant
Summary Micro RNA s (mi RNA s) are 20–24 nt non‐coding RNA s that play important regulatory roles in a broad range of eukaryotes by pairing with m RNA s to direct post‐transcriptional repression. The mechanistic details of mi RNA ‐mediated post‐transcriptional regulation have been well documented in multicellular model organisms. However, this process remains poorly studied in algae such as Chlamydomonas reinhardtii , and specific features of mi RNA biogenesis, target m RNA recognition and subsequent silencing are not well understood. In this study, we report on the characterization of a Chlamydomonas mi RNA , cre‐miR1174.2, , which is processed from a near‐perfect hairpin RNA . Using Gaussia luciferase ( gluc ) reporter genes, we have demonstrated that cre‐miR1174.2 is functional in Chlamydomonas and capable of triggering site‐specific cleavage at the center of a perfectly complementary target sequence. A mismatch tolerance test assay, based on pools of transgenic strains, revealed that target hybridization to nucleotides of the seed region, at the 5′ end of an mi RNA , was sufficient to induce moderate repression of expression. In contrast, pairing to the 3′ region of the mi RNA was not critical for silencing. Our results suggest that the base‐pairing requirements for small RNA ‐mediated repression in C. reinhardtii are more similar to those of metazoans compared with the extensive complementarity that is typical of land plants. Individual Chlamydomonas mi RNA s may potentially modulate the expression of numerous endogenous targets as a result of these relaxed base‐pairing requirements.