A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backwards). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds.
An aminoacyl-tRNA synthetase, also called tRNA-ligase, is an enzyme that attaches the appropriate amino acid onto its corresponding tRNA. It does so by catalyzing the transesterification of a specific cognate amino acid or its precursor to one of all its compatible cognate tRNAs to form an aminoacyl-tRNA. In humans, the 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases, one for each amino acid of the genetic code.
The genome and proteins of HIV (human immunodeficiency virus) have been the subject of extensive research since the discovery of the virus in 1983. "In the search for the causative agent, it was initially believed that the virus was a form of the Human T-cell leukemia virus (HTLV), which was known at the time to affect the human immune system and cause certain leukemias. However, researchers at the Pasteur Institute in Paris isolated a previously unknown and genetically distinct retrovirus in patients with AIDS which was later named HIV." Each virion comprises a viral envelope and associated matrix enclosing a capsid, which itself encloses two copies of the single-stranded RNA genome and several enzymes. The discovery of the virus itself occurred two years following the report of the first major cases of AIDS-associated illnesses.
This family represents the bovine leukaemia virus RNA encapsidation (packaging) signal, which is essential for efficient viral replication.
The retroviral psi packaging element, also known as the Ψ RNA packaging signal, is a cis-acting RNA element identified in the genomes of the retroviruses Human immunodeficiency virus (HIV) and Simian immunodeficiency virus (SIV). It is involved in regulating the essential process of packaging the retroviral RNA genome into the viral capsid during replication. The final virion contains a dimer of two identical unspliced copies of the viral genome.
HIV gag stem loop 3 (GSL3) is a secondary structural component of the Retroviral Psi packaging element, also known as the psi recognition element. This domain plays a major role in RNA packaging and is located the 5’ untranslated region of the unspliced HIV-1 genome. GSL3 is known to direct specific packaging of HIV-1 genomic RNA. While deletion of GSL3 leads to decreases in both viral RNA packaging and dimerization, mutagenic studies have shown that it does not eliminate encapsulation of retroviral RNA.
Elongation factor 1-delta is a protein that in humans is encoded by the EEF1D gene.
Lysyl-tRNA synthetase is an enzyme that in humans is encoded by the KARS gene.
Aspartyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the DARS gene.
Leucyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the LARS gene.
Glutaminyl-tRNA synthetase is an enzyme that in humans is encoded by the QARS gene.
Methionyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the MARS gene.
Threonyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the TARS gene.
Isoleucyl-tRNA synthetase, cytoplasmic is an enzyme that in humans is encoded by the IARS1 gene.
In molecular biology, Tat is a protein that is encoded for by the tat gene in HIV-1. Tat is a regulatory protein that drastically enhances the efficiency of viral transcription. Tat stands for "Trans-Activator of Transcription". The protein consists of between 86 and 101 amino acids depending on the subtype. Tat vastly increases the level of transcription of the HIV dsDNA. Before Tat is present, a small number of RNA transcripts will be made, which allow the Tat protein to be produced. Tat then binds to cellular factors and mediates their phosphorylation, resulting in increased transcription of all HIV genes, providing a positive feedback cycle. This in turn allows HIV to have an explosive response once a threshold amount of Tat is produced, a useful tool for defeating the body's response.
Rev is a transactivating protein that is essential to the regulation of HIV-1 protein expression. A nuclear localization signal is encoded in the rev gene, which allows the Rev protein to be localized to the nucleus, where it is involved in the export of unspliced and incompletely spliced mRNAs. In the absence of Rev, mRNAs of the HIV-1 late (structural) genes are retained in the nucleus, preventing their translation.
Susan A. Martinis is an American biochemist. She has co-authored over 57 publications in peer reviewed journals and scientific book chapters. Her expertise is in protein:RNA interactions and aminoacyl tRNA synthetases. As of 2019, she is the Vice Chancellor for Research and Innovation at the University of Illinois at Urbana-Champaign.
Leslie J. Parent is an American microbiologist and immunologist currently professor and vice dean of the College of Medicine at Pennsylvania State University and an Elected Fellow of the American Association for the Advancement of Science and American Society for Microbiology.
Paul Darren Bieniasz is a British-American virologist whose main area of research is HIV/AIDS. He is currently a professor of retrovirology at the Rockefeller University. He received the 2015 KT Jeang Retrovirology Prize and the 2010 Eli Lilly and Company Research Award. Bieniasz has been a Howard Hughes Medical Institute investigator since 2008.
Xiang-Lei Yang (杨湘磊) is a Chinese-born American molecular biologist. She is a professor at The Scripps Research Institute, located in La Jolla, California. Her work has contributed to the establishment of physiological importance of aminoacyl-tRNA synthetases beyond their classical role in supporting mRNA translation and their disordered processes that contribute to disease. She founded the Translation Machinery in Health and Disease Gordon Research Conference, an ongoing biannual international conference since 2015. She helped co-found aTyr Pharma, a Nasdaq-listed biotechnology company.
