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Biology subjects

Arunachalam Ramaiah

Publications and source records attributed to Arunachalam Ramaiah.

2 recordsLinked to original sources

Dysregulation of Long Non-coding RNA (lncRNA) Genes and Predicted lncRNA-protein Interactions during Zika Virus Infection

Zika Virus (ZIKV) is a causative agent for poor pregnancy outcome and fetal developmental abnormalities, including microcephaly and eye defects. As a result, ZIKV is now a confirmed teratogen. Understanding host-pathogen interactions, specifically cellular perturbations caused by ZIKV, can provide novel therapeutic targets. In order to complete viral replication, viral pathogens control the host cellular machineries and regulate various factors, including long noncoding RNA (lncRNA) genes, at transcriptional levels. The role of lncRNA genes in the pathogenesis of ZIKV-mediated microcephaly and eye defects is currently unknown. To gain additional insights, we focused on profiling the differentially expressed lncRNA genes during ZIKV infection in mammalian cells. For this study, we employed a contemporary clinical Zika viral isolate, PRVABC59, of Asian genotype. We utilized an unbiased RNA sequencing approach to profile the lncRNA transcriptome in ZIKV infected Vero cells. We identified a total of 121 lncRNA genes that are differentially regulated at 48 hours post-infection. The majority of these genes are independently validated by reverse-transcription qPCR. A notable observation was that the lncRNAs, MALAT1 (Metastasis Associated Lung Adenocarcinoma Transcript 1) and NEAT1 (Nuclear Paraspeckle Assembly Transcript 1), are down-regulated upon Zika viral infection. MALAT1 and NEAT1 are known as nuclear localized RNAs that regulate gene expression and cell proliferation. Protein-lncRNA interaction maps revealed that MALAT1 and NEAT1 share common interacting partners and form a larger network comprising of 71 cellular factors. ZIKV-mediated dysregulation of these two regulatory lncRNAs can alter the expression of respective target genes and associated biological functions, an important one being cell division. In conclusion, this investigation is the first to provide insight into the biological connection of lncRNAs and ZIKV which can be further explored for developing antiviral therapy and understanding fetal developmental processes.

Microbiology

Comparative analysis of protein evolution and RNA structural changes in the genome of pre-epidemic and epidemic Zika virus

Zika virus (ZIKV) infection is associated with microcephaly, neurological disorders and poor pregnancy outcome1-3 and no vaccine is available. Although ZIKV was first discovered in 1947, the exact mechanism of virus replication and pathogenesis still remains unknown. Recent outbreaks of Zika virus in the Americas clearly suggest a better adaptation of viral strains to human host. Understanding the conserved and adaptive features in the evolution of ZIKV genome will reveal the molecular mechanism of virus replication and host adaptation. Here, we show comprehensive analysis of protein evolution and changes in RNA secondary structures of ZIKV strains including the current 2015-16 outbreak. To identify the constraints on ZIKV evolution, selection pressure at individual codons, immune epitopes, co-evolving sites, and RNA structures were analyzed. The proteome of current 2015/16 epidemic ZIKV strains of Asian genotype is found to be genetically conserved due to genome-wide negative selection on codons, with limited positive selection. Predicted RNA structures at the 5 and 3 ends of ZIKV strains reveal substantial changes such as an additional stem loop which makes it similar to that of Yellow Fever Virus. Concisely, the targeted changes at both the amino acid and the RNA levels contribute to the better adaptation of ZIKV strains to human host with an enhanced neurotropism.

Microbiology