15 research outputs found
Transposable elements versus the fungal genome: impact on whole-genome architecture and transcriptional profiles
Incluye 10 ficheros de datosTransposable elements (TEs) are exceptional contributors to eukaryotic genome diversity.
Their ubiquitous presence impacts the genomes of nearly all species and mediates genome
evolution by causing mutations and chromosomal rearrangements and by modulating gene
expression. We performed an exhaustive analysis of the TE content in 18 fungal genomes,
including strains of the same species and species of the same genera. Our results depicted
a scenario of exceptional variability, with species having 0.02 to 29.8% of their genome consisting
of transposable elements. A detailed analysis performed on two strains of Pleurotus
ostreatus uncovered a genome that is populated mainly by Class I elements, especially
LTR-retrotransposons amplified in recent bursts from 0 to 2 million years (My) ago. The preferential
accumulation of TEs in clusters led to the presence of genomic regions that lacked
intra- and inter-specific conservation. In addition, we investigated the effect of TE insertions
on the expression of their nearby upstream and downstream genes. Our results showed
that an important number of genes under TE influence are significantly repressed, with
stronger repression when genes are localized within transposon clusters. Our transcriptional
analysis performed in four additional fungal models revealed that this TE-mediated
silencing was present only in species with active cytosine methylation machinery. We
hypothesize that this phenomenon is related to epigenetic defense mechanisms that are
aimed to suppress TE expression and control their proliferation.This work was supported by Spanish
National Research Plan (Projects AGL2011-30495
and AGL2014-55971-R) and FEDER funds; Public
University of Navarre; U.S.
Department of Energy Joint Genome Institute; and
Office of Science of the U.S. Department of Energy
under Contract No. DE-AC02-05CH11231.