RNA splicing, via transesterification reactions
Definition
Target type: biologicalprocess
Splicing of RNA via a series of two transesterification reactions. [GOC:krc]
RNA splicing is a crucial process in gene expression that removes non-coding sequences (introns) from pre-messenger RNA (pre-mRNA) molecules, leaving behind the protein-coding sequences (exons) to form mature mRNA. This process is catalyzed by a large ribonucleoprotein complex called the spliceosome. The spliceosome consists of five small nuclear ribonucleoproteins (snRNPs), U1, U2, U4, U5, and U6, and numerous protein factors. The splicing reaction proceeds through two sequential transesterification reactions, where a phosphodiester bond is broken and formed. In the first step, the 2'-hydroxyl group of the adenine nucleotide at the branch point within the intron attacks the 5' splice site, cleaving the phosphodiester bond between the 5' exon and the intron. This reaction forms a lariat structure, where the intron is circularized by a 2'-5' phosphodiester bond. In the second step, the 3'-hydroxyl group of the 5' exon attacks the 3' splice site, cleaving the intron from the 3' exon. This reaction joins the two exons together, forming the mature mRNA, and releases the intron lariat. The spliceosome utilizes a complex interplay of RNA-RNA, RNA-protein, and protein-protein interactions to facilitate the precise recognition of splice sites, promote the correct alignment of exons, and catalyze the transesterification reactions. This sophisticated mechanism ensures that the correct protein is synthesized from the genetic code. This process, known as splicing, is highly regulated and can lead to the production of different mRNA transcripts from the same pre-mRNA molecule through alternative splicing. This allows for the generation of a diverse proteome from a limited number of genes. The process of RNA splicing is essential for proper gene expression and is crucial for the development and function of all living organisms.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Splicing factor 3B subunit 3 | A splicing factor 3B subunit 3 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q15393] | Homo sapiens (human) |
Compounds (4)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| trichostatin a | trichostatin A: chelates zinc ion in the active site of histone deacetylases, resulting in preventing histone unpacking so DNA is less available for transcription; do not confuse with TRICHOSANTHIN which is a protein; found in STREPTOMYCES | antibiotic antifungal agent; hydroxamic acid; trichostatin | bacterial metabolite; EC 3.5.1.98 (histone deacetylase) inhibitor; geroprotector |
| tacrolimus | tacrolimus (anhydrous) : A macrolide lactam containing a 23-membered lactone ring, originally isolated from the fermentation broth of a Japanese soil sample that contained the bacteria Streptomyces tsukubaensis. Tacrolimus: A macrolide isolated from the culture broth of a strain of Streptomyces tsukubaensis that has strong immunosuppressive activity in vivo and prevents the activation of T-lymphocytes in response to antigenic or mitogenic stimulation in vitro. | macrolide lactam | bacterial metabolite; immunosuppressive agent |
| lactacystin | lactam; S-substituted L-cysteine | ||
| e 7107 | E 7107: has antineoplastic activity |