Subjects: Biology >> Biophysics >> Cell Biology submitted time 2016-05-12
Zhang, Peng
Wang, Jiajia
Huang, Da-Wei
He, Shunmin
Kang, Jun-Yan
Gou, Lan-Tao
Dai, Peng
Liu, Mo-Fang
Kang, Jun-Yan
Gou, Lan-Tao
Dai, Peng
Liu, Mo-Fang
Skogerboe, Geir
Chen, Runsheng
Xue, Yuanchao
Fu, Xiang-Dong
Xue, Yuanchao
Fu, Xiang-Dong
Abstract： The piRNA machinery is known for its role in mediating epigenetic silencing of transposons. Recent studies suggest that this function also involves piRNA-guided cleavage of transposon-derived transcripts. As many piRNAs also appear to have the capacity to target diverse mRNAs, this raises the intriguing possibility that piRNAs may act extensively as siRNAs to degrade specific mRNAs. To directly test this hypothesis, we compared mouse PIWI (MIWI)-associated piRNAs with experimentally identified cleaved mRNA fragments from mouse testes, and observed cleavage sites that predominantly occur at position 10 from the 5' end of putative targeting piRNAs. We also noted strong biases for U and A residues at nucleotide positions 1 and 10, respectively, in both piRNAs and mRNA fragments, features that resemble the pattern of piRNA amplification by the 'ping-pong' cycle. Through mapping of MIWI-RNA interactions by CLIP-seq and gene expression profiling, we found that many potential piRNA-targeted mRNAs directly interact with MIWI and show elevated expression levels in the testes of Miwi catalytic mutant mice. Reporter-based assays further revealed the importance of base pairing between piRNAs and mRNA targets and the requirement for both the slicer activity and piRNA-loading ability of MIWI in piRNA-mediated target repression. Importantly, we demonstrated that proper turnover of certain key piRNA targets is essential for sperm formation. Together, these findings reveal the siRNA-like function of the piRNA machinery in mouse testes and its central requirement for male germ cell development and maturation.
Peer Review Status:
Awaiting Review
Subjects: Biology >> Biophysics >> Biology submitted time 2016-05-05
Abstract： Recent deep sequencing surveys of mammalian genomes have unexpectedly revealed pervasive and complex transcription and identified tens of thousands of RNA transcripts that do not code for proteins. These non-coding RNAs (ncRNAs) highlight the central role of RNA in gene regulation. ncRNAs are arbitrarily divided into two main groups: The first includes small RNAs, such as miRNAs, piRNAs, and endogenous siRNAs, that usually range from 20 to 30 nt, while the second group includes long non-coding RNAs (lncRNAs), which are typically more than 200 nt in length. These ncRNAs were initially thought to merely regulate gene expression at the post-transcriptional level, but recent studies have indicated that ncRNAs, especially lncRNAs, are extensively associated with diverse chromatin remodeling complexes and target them to specific genomic loci to alter DNA methylation or histone status. These findings suggest an emerging theme of ncRNAs in epigenetic regulation. In this review, we discuss the wide spectrum of ncRNAs in the regulation of DNA methylation and chromatin state, as well as the key questions that needs to be investigated and acknowledging the elegant design of these intriguing macromolecules.
Peer Review Status:Awaiting Review
Subjects: Biology >> Biophysics >> Neurosciences submitted time 2016-05-05
Lim, Su Min
Kim, Seung Hyun
Lim, Su Min
Oh, Ki-Wook
Choi, Ji Young
Kim, Sung Hoon
Nahm, Minyeop
Noh, Min-Young
Kim, Seung Hyun
Choi, Won Jun
Oh, Ki-Wook
Kim, Seung Hyun
Xue, Yuanchao
Kim, Young-Eun
Ki, Chang-Seok
Lee, Jinhyuk
Lee, Jinhyuk
Lee, Seungbok
Hwang, Sejin
Fu, Xiang-Dong
Abstract： Background: Mutations in the fused in sarcoma (FUS) gene have been linked to amyotrophic lateral sclerosis (ALS). ALS patients with FUS mutations exhibit neuronal cytoplasmic mislocalization of the mutant FUS protein. ALS patients' fibroblasts or induced pluripotent stem cell (iPSC)-derived neurons have been developed as models for understanding ALS-associated FUS (ALS-FUS) pathology; however, pathological neuronal signatures are not sufficiently present in the fibroblasts of patients, whereas the generation of iPSC-derived neurons from ALS patients requires relatively intricate procedures. Results: Here, we report the generation of disease-specific induced neurons (iNeurons) from the fibroblasts of patients who carry three different FUS mutations that were recently identified by direct sequencing and multi-gene panel analysis. The mutations are located at the C-terminal nuclear localization signal (NLS) region of the protein (p.G504Wfs*12, p.R495*, p.Q519E): two de novo mutations in sporadic ALS and one in familial ALS case. Aberrant cytoplasmic mislocalization with nuclear clearance was detected in all patient-derived iNeurons, and oxidative stress further induced the accumulation of cytoplasmic FUS in cytoplasmic granules, thereby recapitulating neuronal pathological features identified in mutant FUS (p.G504Wfs*12)-autopsied ALS patient. Importantly, such FUS pathological hallmarks of the patient with the p.Q519E mutation were only detected in patient-derived iNeurons, which contrasts to predominant FUS (p.Q519E) in the nucleus of both the transfected cells and patient-derived fibroblasts. Conclusions: Thus, iNeurons may provide a more reliable model for investigating FUS mutations with disrupted NLS for understanding FUS-associated proteinopathies in ALS.
Peer Review Status:Awaiting Review
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