Project description:Human sperm RNA-seq was performed and sequences used for the generation of a RNA integrity index capable of assessing samples with high RNA fragmentation. A two-prong approach was used including both manual and computational analysis. This identified a series of sperm RNAs that are consistently intact, and acceptable for use in determining sample RNA quality. These RNAs function in roles related to spermatogenesis and/or fertilization.
Project description:Maintaining centromere integrity is crucial for genome stability and proper chromosome segregation during mitosis. CENPA, a conserved histone H3 variant, is localized at the centromeres and plays an essential role in preserving centromere integrity and function. However, the mechanisms that retain CENPA at centromeres remain an enigma. In this study, we identified CENPA as an m6A reader of centromeric RNA (cenRNA), which is essential for its centromeric localization and function in maintaining centromere stability. We discovered a higher level of m6A modification on cenRNA in cancerous cells compared to normal cells. CENPA preferentially binds the cenRNAs with m6A modification, which stabilizes its localization in centromeric regions during the S phase of the cell cycle. We then identified two residues in CENPA responsible for m6A recognition. Mutations in these CENPA residues or removal of m6A on cenRNAs leads to the loss of centromere-bound CENPA during the S phase, thereby resulting in abnormal chromosome separation during mitosis and increased genomic instability. Consequently, this impairment in centromere integrity hindered cancer cell proliferation and tumor growth. Our findings unveiled a novel m6A reading mechanism by CENPA that epigenetically governs centromere integrity in cancer cells, providing potentially new targets for cancer therapy.
Project description:Maintaining centromere integrity is crucial for genome stability and proper chromosome segregation during mitosis. CENPA, a conserved histone H3 variant, is localized at the centromeres and plays an essential role in preserving centromere integrity and function. However, the mechanisms that retain CENPA at centromeres remain an enigma. In this study, we identified CENPA as an m6A reader of centromeric RNA (cenRNA), which is essential for its centromeric localization and function in maintaining centromere stability. We discovered a higher level of m6A modification on cenRNA in cancerous cells compared to normal cells. CENPA preferentially binds the cenRNAs with m6A modification, which stabilizes its localization in centromeric regions during the S phase of the cell cycle. We then identified two residues in CENPA responsible for m6A recognition. Mutations in these CENPA residues or removal of m6A on cenRNAs leads to the loss of centromere-bound CENPA during the S phase, thereby resulting in abnormal chromosome separation during mitosis and increased genomic instability. Consequently, this impairment in centromere integrity hindered cancer cell proliferation and tumor growth. Our findings unveiled a novel m6A reading mechanism by CENPA that epigenetically governs centromere integrity in cancer cells, providing potentially new targets for cancer therapy.
Project description:Achieved biospecimens annotated with patient clinical characteristics are unique resources for translational research. However, RNA extracted from the achieved tissues is often degraded. RNA degradation can have a significant impact on the measure of transcript abundance that can lead to an increase rate of erroneous differentially expressed genes. Here, we are presenting the transcript integrity number (TIN) algorithm to measure the RNA degradation at transcript level. When applied to RNA-seq datasets generated from human brain Glioblastome cell line, human peripheral blood mononuclear cells, and metastatic castration resistant prostate cancer (mCRPC) clinical tissues, TIN provided a more reliable and more sensitive measure of RNA degradation than RIN, as demonstrated by much higher concordance with the RNA fragment size estimated from read pairs. More importantly, when comparing 10 mCRPC samples with lower RNA quality to another 10 samples with higher RNA quality, we demonstrated that calibrating gene quantification with TIN scores could mitigate RNA degradation effects and greatly improve gene expression analysis. The detected differentially expressed genes before TIN correction were predominantly ribosomal genes. However, when we adjusted gene quantifications with the corresponding TIN scores, we found differentially expressed genes were highly enriched in prostate cancer specific pathways. When further evaluating the performance of TIN correction using synthetic spike-in transcripts with predetermined abundance in RNA-seq data generated from Sequencing Control Consortium (SEQC), we found TIN adjustment had a better control of false positives and false negatives (sensitivity = 0.89, specificity = 0.91), as compared to gene expression analysis results without TIN correction (sensitivity =0.98, specificity = 0.50). RNA sequencing of 20 bone-metastatic castration resistant prostate cancer (mCRPC) using Illumina HiSeq 2500. Out of 20 mCRPC samples, 10 samples have relative low RNA integrity and another 10 samples have relative higher RNA integrity as measured by Agilent RIN score.