Expression of Transposable Elements in Neural Tissues during Xenopus Development

Abstract

Transposable elements comprise a large proportion of animal genomes. Transposons can have detrimental effects on genome stability but also offer positive roles for genome evolution and gene expression regulation. Proper balance of the positive and deleterious effects of transposons is crucial for cell homeostasis and requires a mechanism that tightly regulates their expression. Herein we describe the expression of DNA transposons of the Tc1/mariner superfamily during Xenopus development. Sense and antisense transcripts containing complete Tc1-2_Xt were detected in Xenopus embryos. Both transcripts were found in zygotic stages and were mainly localized in Spemann's organizer and neural tissues. In addition, the Tc1-like elements Eagle, Froggy, Jumpy, Maya, Xeminos and TXr were also expressed in zygotic stages but not oocytes in X. tropicalis. Interestingly, although Tc1-2_Xt transcripts were not detected in Xenopus laevis embryos, transcripts from other two Tc1-like elements (TXr and TXz) presented a similar temporal and spatial pattern during X. laevis development. Deep sequencing analysis of Xenopus tropicalis gastrulae showed that PIWI-interacting RNAs (piRNAs) are specifically derived from several Tc1-like elements. The localized expression of Tc1-like elements in neural tissues suggests that they could play a role during the development of the Xenopus nervous system.

Emerging roles of non-coding RNAs in brain evolution, development, plasticity and disease

“…For example, one remarkable study recently identified thousands of reintegration sites for LINE-1 (L1), Alu and composite SVA (SINE, VNTR and Alu ) elements in the human caudate and hippocampus 68 . These findings are consistent with previous reports suggesting that retrotransposon activity is important for neural development and plasticity 69–71 . In addition, they also indicate that retrotransposon-derived ncRNAs and ncRNAs that are responsible for regulating retrotransposition events (via endo-siRNAs and piRNAs) mediate in neurons and act as regulatory control systems for the establishment, maintenance and plasticity of the transcriptional architecture of the brain.…”

BARE1andBAGY2Retrotransposon Movements and Expression Analyses in Developing Barley Seedlings

“…Faunes et al (9) reported different expression profiles of Tc1 family transposons in the nervous system of Xenopus tropicalis. the importance of the developmental regulation in the expression of the transposons in the corn plant was shown by li et al (17).…”

Expression of DNA transposable elements during nervous system development

“…We extended these observations by showing that a DNA transposable element of the Tc 1/ mariner family is differentially expressed during X. tropicalis development 8 , 9 . The general structure of Tc 1/ mariner elements is shown in Figure 1A.…”