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Biology

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2006

Protein binding

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Modification Of Human Immunodeficiency Virus Type 1 Reverse Transcriptase To Target Cells With Elevated Cellular Dntp Concentrations, Varuni K. Jamburuthugoda, Pauline Chugh, Baek Kim Jan 2006

Modification Of Human Immunodeficiency Virus Type 1 Reverse Transcriptase To Target Cells With Elevated Cellular Dntp Concentrations, Varuni K. Jamburuthugoda, Pauline Chugh, Baek Kim

Biology

Retroviruses and DNA viruses utilize cellular dNTPs as substrates for their DNA polymerases during viral replication in infected cells. However, because of S phase-dependent dNTP biosynthesis, the availability of cellular dNTPs significantly varies among cell types (e.g. dividing versus nondividing cells and normal versus tumor cells). Here we tested whether alterations in the dNTP utilization efficiency and dNTP binding affinity of viral DNA polymerases can switch viral infection specificity to cell types with different dNTP concentrations. We employed an HIV-1 reverse transcriptase (RT) mutant (Q151N), which is catalytically active only at high dNTP concentrations because of its reduced dNTP binding …


Krepa4, An Rna Binding Protein Essential For Editosome Integrity And Survival Of Trypanosoma Brucei, Rezaq Salavati, Nancy Lewis Ernst, Jeffrey O'Rear, Troy Gilliam, Salvador Tarun Jr., Kenneth Stuart, K. Jan 2006

Krepa4, An Rna Binding Protein Essential For Editosome Integrity And Survival Of Trypanosoma Brucei, Rezaq Salavati, Nancy Lewis Ernst, Jeffrey O'Rear, Troy Gilliam, Salvador Tarun Jr., Kenneth Stuart, K.

Biology

The 20S editosome, a multiprotein complex, catalyzes the editing of most mitochondrial mRNAs in trypanosomatids by uridylate insertion and deletion. RNAi mediated inactivation of expression of KREPA4 (previously TbMP24), a component of the 20S editosome, in procyclic form Trypanosoma brucei resulted in inhibition of cell growth, loss of RNA editing, and disappearance of 20S editosomes. Levels of MRP1 and REAP-1 proteins, which may have roles in editing but are not editosome components, were unaffected. Tagged KREPA4 protein is incorporated into 20S editosomes in vivo with no preference for either insertion or deletion subcomplexes. Consistent with its S1-like motif, recombinant KREPA4 …