Zebrafish 2.25 dpf embryos: controls vs. med14 mutants

ABSTRACT: Transcriptional profiling of 2.25 dpf (days post fertilzation) zebrafish embryos comparing wildtype (control) to med14 (mediator complex subunit 14) mutants. Goal was to determine the extent to which transcription was affected in med14 mutants by analyzing global gene expression. Background: Mediator is an evolutionarily conserved multi-subunit complex that physically links the RNA polymerase II transcriptional machinery to enhancer bound regulatory factors. While classically described as a core component of the transcriptional machinery, recent evidence suggests that Mediator may have context-dependent roles. In particular, a requirement for Mediator in the maintenance of embryonic and induced pluripotent stem cells has been noted. However, the in vivo consequences of loss of function of many Mediator subunits are unknown. Results: We identified med14, which encodes a Mediator subunit, as the gene affected in the zebrafish logelei (log) mutant. log mutants displayed a morphological arrest by 2 days of embryonic development. Surprisingly, microarray analysis showed that transcription was not broadly affected in log mutants. Transplanted log cells placed into a wild-type environment were able to survive into adulthood, suggesting a lack of global transcriptional defects in Med14-deficient cells. RNAi knockdown of the single med14 ortholog in planarians demonstrated that med14 was required for adult stem cell maintenance and regeneration. A broader assay of Mediator subunits revealed that many were required for stem cell maintenance in planarians. Multiple stem/progenitor cell populations were observed to be reduced or absent in zebrafish med14 mutant embryos, with embryonic fin regeneration defects also evident. Conclusions: Taken together, our results show a critical, evolutionarily conserved, function for Med14 (and perhaps Mediator in general) in evolutionarily conserved in vivo stem cell maintenance and regeneration, distinct from a ubiquitous role in transcription.

ORGANISM(S): Danio rerio

PROVIDER: GSE58042 | GEO | 2017/02/09

SECONDARY ACCESSION(S): PRJNA248750

REPOSITORIES: GEO