Search results
Results from the WOW.Com Content Network
RNA polymerase, assisted by one or more general transcription factors, then selects a transcription start site in the transcription bubble, binds to an initiating NTP and an extending NTP (or a short RNA primer and an extending NTP) complementary to the transcription start site sequence, and catalyzes bond formation to yield an initial RNA product.
A reverse transcriptase (RT) is an enzyme used to convert RNA genome to DNA, a process termed reverse transcription.Reverse transcriptases are used by viruses such as HIV, COVID-19, and hepatitis B to replicate their genomes, by retrotransposon mobile genetic elements to proliferate within the host genome, and by eukaryotic cells to extend the telomeres at the ends of their linear chromosomes.
The chemical structure of RNA is very similar to that of DNA, but differs in three primary ways: Unlike double-stranded DNA, RNA is usually a single-stranded molecule (ssRNA) [4] in many of its biological roles and consists of much shorter chains of nucleotides. [5]
5' cap structure. A 5' cap (also termed an RNA cap, an RNA 7-methylguanosine cap, or an RNA m 7 G cap) is a modified guanine nucleotide that has been added to the "front" or 5' end of a eukaryotic messenger RNA shortly after the start of transcription. The 5' cap consists of a terminal 7-methylguanosine residue that is linked through a 5'-5 ...
The transcription of rRNA genes takes place in a specialised structure of the nucleus called the nucleolus, [5] where the transcribed rRNAs are combined with proteins to form ribosomes. [6] RNA polymerase II (Pol II) is responsible for the transcription of all mRNAs, some snRNAs, siRNAs, and all miRNAs.
The diagram includes 8 RNA polymerases however the number can vary depending on cell type. The image also includes transcription factors and a porous, protein core. Transcription factories, in genetics describe the discrete sites where transcription occurs in the cell nucleus, and are an example of a biomolecular condensate.
Each strand of DNA or RNA has a 5' end and a 3' end, so named for the carbon position on the deoxyribose (or ribose) ring. By convention, upstream and downstream relate to the 5' to 3' direction respectively in which RNA transcription takes place. [1] Upstream is toward the 5' end of the RNA molecule, and downstream is toward the 3
Several cell function specific transcription factor proteins (in 2018 Lambert et al. indicated there were about 1,600 transcription factors in a human cell [41]) generally bind to specific motifs on an enhancer [22] and a small combination of these enhancer-bound transcription factors, when brought close to a promoter by a DNA loop, govern the ...