Editing the Message: RNA Splicing Explained

If the cytoplasm contains enzymes that digest unprotected RNA, then the cell must add a cap and tail. If the original gene contains non-coding segments, then those must be removed to create a functional protein blueprint.

If the 5' cap is required for the mRNA to bind to the ribosome for translation to even begin, then it must be added before translation occurs, typically during transcription.

If a specific chemical "hat" is placed on the 5' end of the RNA to protect it and help the ribosome recognize it, then that structure is defined as the 5' cap.

If a gene is "interrupted" by extra sequences that do not contain protein-building instructions, then those sequences are called introns. If they do not belong in the final message, then they must be cut out.

If the cell can choose to skip certain exons or include different combinations of them, then different mRNA strands are produced from one gene. If different strands are produced, then the cell can create multiple unique proteins from a single DNA sequence.

If the cell requires a massive molecular machine to identify the boundaries of introns and stitch exons together, then that machine is scientifically known as the spliceosome.

If the goal of processing is to create a "mature" message, then non-coding introns are removed. If the promoter is not part of the final protein code but was partially copied, then it is also excluded; however, the cap and tail are added, not removed.

If the DNA template is in the nucleus and the mRNA must be "mature" before it enters the cytoplasm for translation, then all editing steps must occur inside the nucleus.

If introns make up a large portion of the original gene and are removed during splicing, then the resulting mature mRNA has fewer nucleotides. Therefore, the mature strand is significantly shorter than the pre-mRNA.

If the spliceosome is a complex machine, then its individual working parts are snRNPs. If these parts contain RNA and protein and help find the start and end of an intron, then they are essential for splicing.

If one gene can make five different proteins depending on the cell type, then the organism is more complex without needing more DNA. If this allows for specialized proteins in the brain versus the muscle, then it is a major evolutionary benefit.

If the cap is attached "backwards" compared to normal nucleotides, then it uses three phosphate groups to form the link. If this bridge exists, then it is a 5'-to-5' triphosphate bridge.

If the cell is efficient with its resources, then it will not throw away the nucleotides from the removed introns. If enzymes break them down into individual bases, then the cell can use those bases to build new RNA.

If the mRNA needs to survive the journey to the cytoplasm and attach to a ribosome, then it needs protective ends. If these structures provide that protection and identification, then they facilitate export and translation; however, they do not code for amino acids or replicate DNA.

If the sugar-phosphate backbone of the RNA must be made continuous after an intron is removed, then a new covalent bond must form between the nucleotides. If this is a standard nucleic acid bond, then it is a phosphodiester bond.

If the tail consists of many adenines and requires an enzyme to build it without a DNA template, then that enzyme is poly-A polymerase. This is a key part of how rna splicing explained in detail includes tailing.

If the spliceosome needs to know exactly where to cut, then it must look for a chemical marker. If nearly all introns start with GU and end with AG, then those serve as the universal "cut here" signals.

If introns are the sequences that "intervene," then the sequences that stay to be "expressed" are logically named exons.

If bacteria lack a nucleus and begin translating mRNA while it is still being transcribed, then they have no time or space for splicing. Therefore, their genes are generally continuous and lack introns.

If one end of the intron is attached to an internal "branch point" adenine to form a loop with a tail, then it resembles a cowboy's lasso. If it has this shape, then it is scientifically called a lariat.