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Evolutionarily dynamic roles of a PUF RNA‐binding protein in the somatic development of Caenorhabditis briggsae
Author(s) -
Liu Qinwen,
Haag Eric S.
Publication year - 2014
Publication title -
journal of experimental zoology part b: molecular and developmental evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 63
eISSN - 1552-5015
pISSN - 1552-5007
DOI - 10.1002/jez.b.22550
Subject(s) - caenorhabditis elegans , biology , caenorhabditis , genetics , rna interference , somatic cell , gene , rna , gene duplication , germline , rna binding protein , microbiology and biotechnology , mutant
Gene duplication and divergence has emerged as an important aspect of developmental evolution. The genomes of Caenorhabditis nematodes encode an ancient family of PUF RNA‐binding proteins. Most have been implicated in germline development, and are often redundant with paralogs of the same sub‐family. An exception is Cbr‐puf‐2 (one of three Caenorhabditis briggsae PUF‐2 sub‐family paralogs), which is required for development past the second larval stage. Here, we provide a detailed functional characterization of Cbr‐puf‐2 . The larval arrest of Cbr‐puf‐2 mutant animals is caused by inefficient breakdown of bacterial food, which leads to starvation. Cbr‐puf‐2 is required for the normal grinding cycle of the muscular terminal bulb during early larval stages, and is transiently expressed in this tissue. In addition, rescue of larval arrest reveals that Cbr‐puf‐2 also promotes normal vulval development. It is expressed in the anchor cell (which induces vulval fate) and vulval muscles, but not in the vulva precursor cells (VPCs) themselves. This contrasts with the VPC‐autonomous repression of vulval development described for the Caenorhabditis elegans homologs fbf‐1/ 2. These different roles for PUF proteins occur even as the vulva and pharynx maintain highly conserved anatomies across Caenorhabditis , indicating pervasive developmental system drift (DSD). Because Cbr‐PUF‐2 shares RNA‐binding specificity with its paralogs and with C. elegans FBF, we suggest that functional novelty of RNA‐binding proteins evolves through changes in the site of their expression, perhaps in concert with cis ‐regulatory evolution in target mRNAs. J. Exp. Zool. (Mol. Dev. Evol.) 322B: 129–141, 2014 . © 2013 Wiley Periodicals, Inc.