Kwangseog Ahn has completed his PhD from University of Illinois at Urbana-Champaign and postdoctoral studies from The Scripps Research Institute at San Diego. He is a professor of Seoul National University in Korea. He has published more than 70 papers in peer-reviewed journals.
Human SAMHD1 possesses dual enzymatic functions. It acts as both a dGTP-dependent triphosphohydrolase and as an exoribonuclease. The dNTPase function depletes the cellular dNTP pool, which is required for retroviral reverse transcription in differentiated myeloid cells and resting CD4+ T cells; thus this activity mainly plays a role in SAMHD1-mediated retroviral restriction. However, a recent study demonstrated that SAMHD1 directly targets HIV-1 genomic RNA via its RNase activity, and that this function (rather than dNTPase activity) is sufficient for HIV-1 restriction. While HIV-1 genomic RNA is a potent target for SAMHD1 during viral infection, the specificity of SAMHD1-mediated RNase activity during infection by other viruses is unclear. The results of the present study showed that SAMHD1 specifically degrades retroviral genomic RNA in monocyte-derived macrophage-like cells. Consistent with this, SAMHD1 selectively restricted retroviral replication, but did not affect the replication of other common non-retro RNA genome viruses, suggesting that the RNase-mediated antiviral function of SAMHD1 is limited to retroviruses. In addition, neither inhibiting reverse transcription by treatment with several reverse transcriptase inhibitors nor infection with reverse transcriptase -defective HIV-1 altered RNA levels after viral challenge, indicating that the retrovirus-specific RNase function is not dependent on processes associated with retroviral reverse transcription.
Sri Ram A has completed his B.Tech Biotech from K.S.Rangasamy College of Technology, Tamil Nadu. He is pursuing M.Tech Biotech at Amity Institiute of Biotechnology, Noida. He has filed a patent (for the formulation process) for his project entitled Cloning of NBS-LRR gene and its application as a biocontrol agent.
The nucleotide binding site- leucine rich repeat (NBS-LRR) is the disease resistance gene present in plants. One of the major challenges faced by modern agriculture is to achieve not only a satisfactory but also an environment friendly control of plant diseases. Therefore in this work it is aimed to clone NBS-LRR gene from Jatropha to E.coli and use it as the biocontrol agent to overcome these challenges. Jatropha curcus was chosen as the source for NBS-LRR gene because there are about 150 clones of resistance (R) genes present in it. The primer was designed specific to the NBS-LRR gene and it was amplified by Polymerase Chain Reaction (PCR). The amplicon was observed to be 600bp. It was then eluted for ligation with pGEMT vector. Totally 107 colonies were obtained in Blue white screening, out of which 41 were white. Presence of insert was confirmed by PCR confirmation and restriction analysis. The dual culture test was done against Fusarium and activity was compared with Trichoderma and normal E.coli. The transformed E.coli DH5α strain exhibited 64% inhibition which was more efficient than Trichoderma which showed 61% and normal E.coli with 43% inhibition. Therefore the transformed strain was formulated and can be used as a biocontrol agent. Patent was filed for this formulation process.