Question

define these words base on virology

Suppressor tRNA

Methylase (eg of TMV)

Subgenomic mRNA (eg of TMV)

IRES

eIF

primer (eg of polio RNA replication)

Answer 1

Suppressor tRNA: This type of RNA was first identified in 1965. It is that type of tRNA that has a mutation and that mutation is usually found in anticodon but not always there. This mutation results in recognition of a stop codon and insertion of an amino acid at that place. These types of RNA are used in translation, phage biology, and protein engineering studies.

Methylase: DNA methylation is an important paradigm of genetic regulation and manipulation. These enzymes may methylase different bases like cytosine or adenine and therefore have a role in epigenetic regulation. Methylation of different RNA like mRNA, rRNA, tRNA, snoRNA, snRNA, miRNA, tRNA occurs by in different RNA like In addition to as viral RNA species occurs by methylase. However, there are some specific RNA methyltransferases that are used to mark these RNA species for gene manipulation and included in molecular epigenetics. It mostly included 2'-O-methylation, m6A methylation, m1G methylation as well as m5C.

Subgenomic mRNA's: These RNA are actually fragments of the template strand (original RNA). As we are aware of the fact that original template DNA is read from the 3' to the 5' end. However, this type of RNA are produced when transcription starts at the 3' end of the template strand and makes a copy towards the 5' end of the template strand. This results in "jumping" to the end of the template and therefore makes copies of the last nucleotides of the 5' end of the template, (finishing the 3' tail for the newly created strand).

Internal ribosome entry site: It is abbreviated as IRES. It is a fragment of RNA that promotes translation initiation and is dependent on cap. This is also important in translation. As we know, in eukaryotes initiation of translation usually starts at the 5' end of mRNA molecules and recognition of 5' cap is necessary for the assembly of the initiation complex.

Eukaryotic initiation factors (eIFs): These are usually single proteins or are proteins or protein complexes. These are required for eukaryotic protein synthesis. These proteins are used for help ribosomal preinitiation complexes formation and stabilization. Various initiation factors form a complex with the small 40Sribosomal subunit and Met-tRNA_i^Met called the 43S preinitiation complex (43S PIC).

primer (eg of polio RNA replication) : The (+) and (?) strands are synthesised by primers which are actually small protein and among one of them is protein VPg. This protein is uridylylated and this uridylation occurs on tyrosine a hydroxyl group by the poliovirus RNA polymerase. This is found at cis-acting replication element located in a stem-loop in the virus genome.