Institutional Publications

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    Absence of correlation between chimeric RNA and aging
    (MDPI AG, 2017) Huang, Reyna; Kumar, Shailesh; Li, Hui
    Chimeric RNAs have been recognized as a phenomenon not unique to cancer cells. They also exist in normal physiology. Aging is often characterized by deregulation of molecular and cellular mechanisms, including loss of heterochromatin, increased transcriptional noise, less tight control on alternative splicing, and more stress-induced changes. It is thus assumed that chimeric RNAs are more abundant in older people. In this study, we conducted a preliminary investigation to identify any chimeric RNAs with age-based trends in their expression levels in blood samples. A chimeric RNA candidate list generated by bioinformatic analysis indicated the possibility of both negative and positive trends in the expression of chimeric RNAs. Out of this candidate list, five novel chimeric RNAs were successfully amplified in multiple blood samples and then sequenced. Although primary smaller sample sizes displayed some weak trends with respect to age, analysis of quantitative PCR data from larger sample sizes showed essentially no relationship between expression levels and age. Altogether, these results indicate that, contradictory to the common assumption, chimeric RNAs as a group are not all higher in older individuals and that placing chimeric RNAs in the context of aging will be a much more complex task than initially anticipated.
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    Rice PROTEIN L-ISOASPARTYL METHYLTRANSFERASE isoforms differentially accumulate during seed maturation to restrict deleterious isoAsp and reactive oxygen species accumulation and are implicated in seed vigor and longevity
    (John Wiley & Sons, 2016) Petla, Bhanu Prakash; Kamble, Nitin Uttam; Kumar, Meenu; Verma, Pooja; Ghosh, Shraboni; Singh, Ajeet; Rao, Venkateswara; Salvi, Prafull; Kaur, Harmeet; Saxena, Saurabh Chandra; Majee, Manoj
    PROTEIN l-ISOASPARTYL O-METHYLTRANSFERASE (PIMT) is a protein-repairing enzyme involved in seed vigor and longevity. However, the regulation of PIMT isoforms during seed development and the mechanism of PIMT-mediated improvement of seed vigor and longevity are largely unknown. In this study in rice (Oryza sativa), we demonstrate the dynamics and correlation of isoaspartyl (isoAsp)-repairing demands and PIMT activity, and their implications, during seed development, germination and aging, through biochemical, molecular and genetic studies. Molecular and biochemical analyses revealed that rice possesses various biochemically active and inactive PIMT isoforms. Transcript and western blot analyses clearly showed the seed development stage and tissue-specific accumulation of active isoforms. Immunolocalization studies revealed distinct isoform expression in embryo and aleurone layers. Further analyses of transgenic lines for each OsPIMT isoform revealed a clear role in the restriction of deleterious isoAsp and age-induced reactive oxygen species (ROS) accumulation to improve seed vigor and longevity. Collectively, our data suggest that a PIMT-mediated, protein repair mechanism is initiated during seed development in rice, with each isoform playing a distinct, yet coordinated, role. Our results also raise the intriguing possibility that PIMT repairs antioxidative enzymes and proteins which restrict ROS accumulation, lipid peroxidation, etc. in seed, particularly during aging, thus contributing to seed vigor and longevity.