Shulou(Shulou.com)06/01 Report--

This article introduces the relevant knowledge of "miRNA synthesis and miRNA naming methods". In the actual case operation process, many people will encounter such difficulties. Next, let Xiaobian lead you to learn how to deal with these situations! I hope you can read carefully and learn something!

miRNA synthesis, miRNA naming, numbering rules

MicroRNAs (miRNAs) are endogenous, small RNAs of approximately 20-24 nucleotides in length that play a variety of important regulatory roles in cells. Each miRNA can have multiple target genes, and several miRNAs can regulate the same gene. This complex regulatory network can regulate the expression of multiple genes through a single miRNA or finely regulate the expression of a gene through a combination of several miRNAs. MiRNAs are thought to regulate one-third of human genes. Recent studies have shown that about 70% of mammalian miRNAs are located in transcription units (TUs ) , and most of them are located in introns. The positions of some intron miRNAs are highly conserved among different species. miRNAs are not only conserved in gene position, but also show high homology in sequence. The high conservation of miRNAs is closely related to their functional importance. miRNA is closely related to the evolution of its target genes. Studying its evolutionary history will help us to further understand its mechanism and function.

Biosynthesis of miRNAs

miRNA is a small, endogenous, single-stranded RNA of 20-24 nucleotides in length, formed by processing the hairpin initial transcription product, and its sequence is present on the stem of the hairpin stem-loop structure.

In animals, miRNA genes are transcribed under the action of RNA polymerase II to generate miRNA primary transcription products (primary-miRNA), primary-miRNA is processed into miRNA precursor miRNA (pre-miRNA) by Drosha protein in nucleus, pre-miRNA is transported to cytoplasm under the mediation of exportin-5, and is further processed into mature miRNA by dicer enzyme in cytoplasm.

5p and 3p of miRNA

Some miRNA precursors produce a functional mature miRNA in each arm, targeting different sites. At this time, it is necessary to distinguish between "-5p" and "-3p" respectively. Such as hsa-miR-21- 5p and hsa-miR-21- 3p, indicate processing from the 5'and 3' arms of the hsa-mir-21 precursor, respectively.

miRNA naming

1)miRNA mature body naming rules (take animal miRNA as an example:

① miRNAs discovered before the naming rules are determined will retain their original names, such as hsa-let-7

②miRNA mature is abbreviated as miR, and then Arabic numerals are added according to its species name and the order of discovery, such as hsa-miR-122.

③ Highly homologous miRNAs have lower case letters (a,b,c,…) after numbers, such as hsa-miR-34a, hsa-miR-34b, hsa-miR-34c, etc.

④ miRNAs with the same mature sequence transcribed from DNA sequences on different chromosomes are distinguished by Arabic numerals at the back, such as hsa-miR-199a-1 and hsa-miR-199a-2.

Usually a miRNA precursor is about 70~80nt in length, and it is likely that the two arms produce miRNAs separately: if there is no obvious expression difference, they are named "-5p" and "-3p" respectively. such as hsa-mir-26b-5p and hsa-miR-26b-3p, respectively, indicating that the hsa-mir-26b precursor is processed from the 5'and 3' end arms, respectively.

2) miRNA number

① miRNA precursor

miRNA precursor transcripts with hairpin structures are named "mir" and numbered "MI," e.g., the precursor ID of human miRNA 122 is hsa-mir-122, Accession is MI0000442

② miRNA mature

miRNA mature bodies of about 20~23nt are named as "miR" and numbered as "MIMAT." For example, human miR-122 has two mature bodies, one of which has ID hsa-miR-122- 5p and Accession MIMAT 000421, and the other has ID hsa-miR-122- 3p and Accession MIMAT000 4590.

The content of "miRNA synthesis and miRNA naming methods" is introduced here. Thank you for reading. If you want to know more about industry-related knowledge, you can pay attention to the website. Xiaobian will output more high-quality practical articles for everyone!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.