TY  - JOUR
A1  - Koziol, Uriel
A1  - Radio, Santiago
A1  - Smircich, Pablo
A1  - Zarowiecki, Magdalena
A1  - Fernández, Cecilia
A1  - Brehm, Klaus
T1  - A novel terminal-repeat retrotransposon in miniature (TRIM) is massively expressed in Echinococcus multilocularis stem cells
JF  - Genome Biology and Evolution
N2  - Taeniid cestodes (including the human parasites Echinococcus spp. and Taenia solium) have very few mobile genetic elements (MGEs) in their genome, despite lacking a canonical PIWI pathway. The MGEs of these parasites are virtually unexplored, and nothing is known about their expression and silencing. In this work, we report the discovery of a novel family of small nonautonomous long terminal repeat retrotransposons (also known as terminal-repeat retrotransposons in miniature, TRIMs) which we have named ta-TRIM (taeniid TRIM). ta-TRIMs are only the second family of TRIM elements discovered in animals, and are likely the result of convergent reductive evolution in different taxonomic groups. These elements originated at the base of the taeniid tree and have expanded during taeniid diversification, including after the divergence of closely related species such as Echinococcus multilocularis and Echinococcus granulosus. They are massively expressed in larval stages, from a small proportion of full-length copies and from isolated terminal repeats that show transcriptional read-through into downstream regions, generating novel noncoding RNAs and transcriptional fusions to coding genes. In E. multilocularis, ta-TRIMs are specifically expressed in the germinative cells (the somatic stem cells) during asexual reproduction of metacestode larvae. This would provide a developmental mechanism for insertion of ta-TRIMs into cells that will eventually generate the adult germ line. Future studies of active and inactive ta-TRIM elements could give the first clues on MGE silencing mechanisms in cestodes.
KW  - Schistosoma mansoni
KW  - molecular characterization
KW  - gene conversion
KW  - nonautonomous
KW  - neoblast
KW  - pluripotency
KW  - retrotransposition
KW  - long noncoding RNA
KW  - epidermal growth factor
KW  - transposable elements
KW  - LTR retrotransposons
KW  - blood fluke
KW  - homologous recombination
KW  - Cestoda Taeniidae
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148306
VL  - 7
IS  - 8
ER  -