Project description:Total RNA (100 μg) were denatured at 70 °C for 5 min and separated by a 15% TBE-Urea gel with 20/100 or 10/60 oligo length standard ladder (Integrated DNA Technologies, Coralville, IA). After visualized by SYBR Gold (Ref. S11494 from Life Technologies), tRFs in gels were cut according to sizes and recovered by small RNA PAGE recovery kit (Zymo Research, Irvine, CA, USA). The recovered tRFs was used to establish the library by NEB small RNA library preparation kit (E7330S).
Project description:Total RNA (100 μg) were denatured at 70 °C for 5 min and separated by a 15% TBE-Urea gel with 20/100 or 10/60 oligo length standard ladder (Integrated DNA Technologies, Coralville, IA). After visualized by SYBR Gold (Ref. S11494 from Life Technologies), tRFs in gels were cut according to sizes and recovered by small RNA PAGE recovery kit (Zymo Research, Irvine, CA, USA). The recovered tRFs was used to establish the library by NEB small RNA library preparation kit (E7330S).
Project description:Background: The oxidative DNA demethylase ALKBH3 targets single-stranded DNA (ssDNA) in order to perform DNA alkylation damage repair. ALKBH3 becomes up-regulated during tumorigenesis and is necessary for proliferation. However, the underlying molecular mechanism remains to be understood. Methods: To further elucidate the function of ALKBH3 in cancer, we performed ChIP-seq to investigate the genomic binding pattern of endogenous ALKBH3 in PC3 prostate cancer cells coupled with microarray experiments to examine the expression effects of ALKBH3 depletion. Results: We demonstrate that ALKBH3 binds to transcription associated locations, such as places of promoter-proximal paused RNA polymerase II and enhancers. Strikingly, ALKBH3 strongly binds to the transcription initiation sites of a small number of highly active gene promoters. These promoters are characterized by high levels of transcriptional regulators, including transcription factors, the Mediator complex, cohesin, histone modifiers and active histone marks. Gene expression analysis showed that ALKBH3 does not directly influence the transcription of its target genes, but its depletion induces an up-regulation of ALKBH3 non-bound inflammatory genes. Conclusions: The genomic binding pattern of ALKBH3 revealed a putative novel hyperactive promoter type. Further, we propose that ALKBH3 is an intrinsic DNA repair protein that suppresses transcription associated DNA damage at highly expressed genes and thereby plays a role to maintain genomic integrity in ALKBH3-overexpressing cancer cells. These results raise the possibility that ALKBH3 may be a potential target for inhibiting cancer progression. PC3 cells were infected with ALKBH3 shRNA or Control shRNA for 48 hours and selected with puromycine. Cells were collected after 48h or 96h past selection.
Project description:Background: The oxidative DNA demethylase ALKBH3 targets single-stranded DNA (ssDNA) in order to perform DNA alkylation damage repair. ALKBH3 becomes up-regulated during tumorigenesis and is necessary for proliferation. However, the underlying molecular mechanism remains to be understood. Methods: To further elucidate the function of ALKBH3 in cancer, we performed ChIP-seq to investigate the genomic binding pattern of endogenous ALKBH3 in PC3 prostate cancer cells coupled with microarray experiments to examine the expression effects of ALKBH3 depletion. Results: We demonstrate that ALKBH3 binds to transcription associated locations, such as places of promoter-proximal paused RNA polymerase II and enhancers. Strikingly, ALKBH3 strongly binds to the transcription initiation sites of a small number of highly active gene promoters. These promoters are characterized by high levels of transcriptional regulators, including transcription factors, the Mediator complex, cohesin, histone modifiers and active histone marks. Gene expression analysis showed that ALKBH3 does not directly influence the transcription of its target genes, but its depletion induces an up-regulation of ALKBH3 non-bound inflammatory genes. Conclusions: The genomic binding pattern of ALKBH3 revealed a putative novel hyperactive promoter type. Further, we propose that ALKBH3 is an intrinsic DNA repair protein that suppresses transcription associated DNA damage at highly expressed genes and thereby plays a role to maintain genomic integrity in ALKBH3-overexpressing cancer cells. These results raise the possibility that ALKBH3 may be a potential target for inhibiting cancer progression.
Project description:Background: The oxidative DNA demethylase ALKBH3 targets single-stranded DNA (ssDNA) in order to perform DNA alkylation damage repair. ALKBH3 becomes up-regulated during tumorigenesis and is necessary for proliferation. However, the underlying molecular mechanism remains to be understood. Methods: To further elucidate the function of ALKBH3 in cancer, we performed ChIP-seq to investigate the genomic binding pattern of endogenous ALKBH3 in PC3 prostate cancer cells coupled with microarray experiments to examine the expression effects of ALKBH3 depletion. Results: We demonstrate that ALKBH3 binds to transcription associated locations, such as places of promoter-proximal paused RNA polymerase II and enhancers. Strikingly, ALKBH3 strongly binds to the transcription initiation sites of a small number of highly active gene promoters. These promoters are characterized by high levels of transcriptional regulators, including transcription factors, the Mediator complex, cohesin, histone modifiers and active histone marks. Gene expression analysis showed that ALKBH3 does not directly influence the transcription of its target genes, but its depletion induces an up-regulation of ALKBH3 non-bound inflammatory genes. Conclusions: The genomic binding pattern of ALKBH3 revealed a putative novel hyperactive promoter type. Further, we propose that ALKBH3 is an intrinsic DNA repair protein that suppresses transcription associated DNA damage at highly expressed genes and thereby plays a role to maintain genomic integrity in ALKBH3-overexpressing cancer cells. These results raise the possibility that ALKBH3 may be a potential target for inhibiting cancer progression.
Project description:RNAs present in mature mammalian sperm are delivered to the zygote at fertilization, where they have the potential to affect early development. The biogenesis of the small RNA payload of mature sperm is therefore of great interest, as it may be a target of signaling pathways linking paternal conditions to offspring phenotype. Recent studies have suggested the surprising hypothesis that the small RNA payload carried by mature sperm may include RNAs that were not synthesized during testicular spermatogenesis, but that are instead delivered to sperm during the process of post-testicular maturation in the epididymis. To further test this hypothesis, we characterized small RNA dynamics during testicular and post-testicular germ cell maturation in mice, confirming and extending prior observations that testicular germ cell populations carry extremely low levels of tRNA fragments (tRFs), which only become highly abundant only after sperm have entered the epididymis. We examined the sperm RNA repertoire in greater detail, finding that the majority of 5’ tRNA fragments carry a 2’-3’ cyclic phosphate at their 3’ end, pointing to a role for RNaseA or T-family nucleases in tRNA cleavage in the male reproductive tract. The process of small RNA delivery to sperm can be recapitulated in vitro, as caput epididymosomes deliver small RNAs including tRFs and microRNAs to mature testicular spermatozoa. Finally, to definitively identify the tissue of origin for small RNAs in sperm, we carried out tissue-specific metabolic labeling of RNAs in intact mice, finding that mature sperm carry small RNAs that were originally synthesized in the somatic cells of the epididymis. Taken together, our data demonstrates that soma-germline small RNA transfer occurs in male mammals, most likely via vesicular transport from the epididymis to maturing sperm.