Name: rna splicing in gene expression
Uploaded: 2023-04-30T18:28:44.000Z
Duration: 2 min 18 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Biology

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms- Structures and Processes

LS.Bio.1.5

Alternative RNA Splicing

RNA splicing is a post-transcriptional mechanism where precursor mRNA, or pre-mRNA, is converted into mature mRNA by removing the introns and re-joining the exons.&#160;
Constitutive RNA splicing joins each exon in their order in the gene to produce a single type of mature mRNA. For example, in a eukaryotic gene with five exons, numbered 1 to 5, constitutive splicing of pre-mRNA will result in a mature mRNA with five exons.
In contrast, alternative RNA splicing uses a single gene to produce multiple types of proteins by joining or removing different combinations of exons and introns to produce distinct mature mRNAs.&#160;
A gene containing five exons might be spliced into a mature mRNA with exons 1 and 5; exons 2, 3 and 5; or exons 1, 3 and 4.&#160; In some cases, the mature mRNA may even contain a retained intron. These variations allow eukaryotic cells to produce a larger assortment of proteins than the number of genes present in their DNA.
Alternative mRNA splicing allows the same gene to produce different tissue-specific forms of the mature mRNA. For example, different variants of alpha tropomyosin are expressed in smooth muscle cells, striated muscle cells, and brain cells.
Alternative RNA s

alternative rna splicing

Alternative RNA splicing is the regulated splicing of exons and introns to produce different mature mRNAs from a single pre-mRNA. Unlike in constitutive splicing where a single gene produces a single type of mRNA, alternative splicing allows an organism to produce multiple proteins from a single gene and plays an important role in protein diversity.
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first type is exon skipping where some exons, along with all the introns, are selectively removed. This is the most prominent type of alternative splicing observed in humans. The second type, intron retention, occurs when a specific intron is retained in the mature mRNA while the others are removed. This type of splicing is more prevalent in plants than humans. In the third and fourth types of alternative splicing, alternative 5&#39; or 3&#8217; splice sites are selected in specific exons, respectively. This change in 5&#39; and 3&#39; splicing sites shortens or lengthens the exon resulting in different types of mature mRNAs. This type of alternative splicing occurs both in humans and plants. The last and rarest type of alternative RNA splicing is mutually exclusive exons where out of two exons, only one is retained while another one was removed.
Alternative splicing is regulated by different cis-acting elements and trans-acting factors. Cis-acting elements are DNA sequences that are present near structural genes whereas trans-acting factors are other molecules that bind to the DNA. In alternative RNA splicing, the cis-acting elements mainly consist of exon and intron specific splicing enhancers and silencers.&#160; Trans-acting factors, like SR proteins (serine/arginine-rich splicing factors), can bind to the exon or intron splicing enhancers to help the splicing machinery to recognize weak splice sites. On the other hand, proteins like heterogeneous nuclear ribo&#173;nucleoproteins bind to the exon or intron splicing silencers to prevent splicing by masking the splice sites from the spliceosome.
Alternative RNA splicing is common in higher eukaryotes. Almost 95% of human genes are alternatively spliced; therefore, defects in the machinery can significantly impair organ function and can result in cancer and other diseases including neurological and heart disorders. In humans,&#160; mutations that directly affect pre-mRNA splicing account for more than 15% of genetic diseases, such as Hutchinson-Gilford progeria and beta-thalassemia.

Alternative RNA splicing is the regulated splicing of exons and introns to produce different mature mRNAs from a single pre-mRNA. Unlike in constitutive ...

Education

JoVE Core

Cell Biology

Unit 1

Transcription: DNA to RNA

KEY TERMS AND CONCEPTS

rna splicing in gene expression

RNA splicing in gene expression helps cells turn one gene into different RNA messages. During RNA processing, introns are removed and exons are joined together. This editing step changes which parts of the RNA stay in the final message.

Alternative splicing gives cells a way to make more than one protein from the same gene. By including or skipping different exons, a cell can produce different RNA versions from one starting transcript. This process adds flexibility to gene expression without changing the DNA sequence.

Some transcripts are spliced in different ways in different cells or at different times. That difference can change the final protein made from the message. RNA splicing is therefore an important part of how cells control which genes are expressed and how those gene products vary.

RNA Splicing in Gene Expression

what is gene expression?

How Cells Control Gene Expression

Cells control gene expression to decide when a gene makes a protein. A gene is a stretch of DNA that holds the instructions for functional RNAs and proteins. Because DNA is built from nucleotides and proteins are built from amino acids, messenger RNA (mRNA) acts as the link between them. The first step is transcription. During transcription, mRNA copies the DNA blueprint. In eukaryotes, this happens in the nucleus through complementary base-pairing with the DNA template. The mRNA is then...

rna structure

RNA Shapes and Protein Synthesis

RNA shapes and protein synthesis are linked through the molecule’s single-stranded structure. RNA is made of ribonucleotides joined by phosphodiester bonds, and it can fold into secondary and tertiary shapes that help control transcription and translation. These shapes are important in both regulation and protein production. Messenger RNA, transfer RNA, and ribosomal RNA are the three main RNA types used in protein synthesis. They all share the same basic build: a single strand of nucleotides.

types of rna

RNA Roles in Protein Synthesis

RNA plays key roles in protein synthesis, and its main forms work together to make proteins in the cell. Messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA) each have a specific job. RNA can also be grouped as protein-coding or non-coding RNA. mRNA is the protein-coding RNA. It carries codons, which are sets of three nucleotides that specify an amino acid. tRNA and rRNA are non-coding RNAs. tRNA acts as an adaptor that reads the mRNA sequence and brings amino acids into the...

transcription

RNA Synthesis and Gene Control

Transcription is the process that makes RNA from a DNA sequence. RNA polymerase carries out this synthesis. It is the first step in turning a gene into a protein, and several other proteins and control sequences help make messenger RNA, or mRNA, correctly. In eukaryotes, DNA is first copied into pre-mRNA. This RNA can then be processed into mature mRNA, which serves as the template for protein synthesis. In prokaryotes, translation into a polypeptide can start before transcription has finished.

bacterial rna polymerase

Bacterial RNA Polymerase and Sigma Factor

Bacterial RNA polymerase carries out transcription, the process of copying DNA into RNA. It is the enzyme that starts RNA synthesis in bacteria and helps control which genes are used. The core enzyme works with a sigma factor, which is a protein that helps the polymerase find the right place to begin. Together, they form the holoenzyme. The sigma factor is important for promoter recognition, so the enzyme can bind near the start of a gene. Once transcription begins, RNA polymerase separates...

eukaryotic rna polymerases

Three Eukaryotic RNA Polymerases

Eukaryotic RNA polymerases are the enzymes that make RNA from DNA in cells with a nucleus. In eukaryotes, this work is divided among three main RNA polymerases. Each enzyme has a specific role in transcription, the process of copying genetic information into RNA. RNA polymerase I makes most ribosomal RNA, or rRNA. RNA polymerase II produces messenger RNA, or mRNA, which carries the instructions for making proteins. RNA polymerase III makes transfer RNA, or tRNA, and also some small RNAs used...

general transcription factors

Tissue-Specific Transcription Factors in Gene Control

Tissue-specific transcription factors help control which genes turn on in different mammal cells. These proteins bind to promoter sequences and can direct a gene to be expressed in one tissue but not another. This selective control helps cells carry out very different jobs in the body. A clear example is the beta globin gene, which makes part of hemoglobin. The gene is present in all body cells, but it is expressed only in red blood cells. That happens because the transcription factors needed...

rna polymerase ii accessory proteins

RNA Polymerase II Helper Proteins

RNA polymerase II helper proteins support the transcription process in eukaryotic cells. They work with RNA polymerase II, the enzyme that makes RNA from a DNA template. These proteins help the enzyme start, move, and finish transcription in the right way. Some helper proteins act as accessory factors. They can assist RNA polymerase II at different stages of gene expression. Their roles are important because transcription must be controlled accurately for cells to make the correct RNA...

transcription elongation factors

RNA Polymerase Pausing and Elongation

RNA polymerase pausing and elongation factors help control how RNA is made from DNA. During transcription, RNA polymerase moves along the gene and builds an RNA strand. Elongation factors support this process by helping the enzyme continue after it pauses. These factors are part of the elongation stage of transcription. They are not the same as the proteins used to start transcription. Their role is to keep RNA polymerase moving so RNA can be copied efficiently. In high school biology, this...

pre-mrna processing: modification of pre-mrna ends

pre-mrna-processing-modification-of-pre-mrna-ends

How Pre-mRNA Becomes Mature mRNA

Pre-mRNA becomes mature mRNA through a series of processing steps in eukaryotic cells. RNA polymerase first makes the transcript, and the RNA is modified before it leaves the nucleus. The unprocessed form is called precursor mRNA, or pre-mRNA, to separate it from mature mRNA. After about 20 to 40 ribonucleotides have been added, enzymes place a cap on the 5' end of the growing RNA. This cap replaces the 5' phosphate with modified guanosine, which carries a methyl group called 7-methyl...

pre-mrna processing: rna splicing

Pre-mRNA Splicing and Intron Removal

Pre-mRNA splicing removes introns from a pre-mRNA molecule and joins the remaining exons together. This step is part of pre-mRNA processing, which helps turn the first RNA copy into a mature message that can be used later in gene expression. Splicing is carried out by the spliceosome, a large RNA-protein complex. The spliceosome recognizes the intron boundaries and cuts out the intron. It then links the exons together in the correct order. A key feature of splicing is the lariat, a looped RNA...

chromatin structure and rna splicing

Chromatin and RNA Splicing Control

Chromatin and RNA splicing work together to shape how genes are used in a cell. Chromatin is the DNA-protein material that packages genetic information, and RNA splicing is a step in which introns are removed from a pre-mRNA transcript. The video explains how chromatin structure can influence this RNA processing step. A compact chromatin structure can make a gene less accessible, while a more open structure can make it easier for the cell to use that gene. This change in access can affect how...

RNA splicing in gene expression helps cells turn one gene into different RNA messages. During RNA processing, introns are removed and exons are joined together. This editing step changes which parts of the RNA stay in the final message. Alternative splicing gives cells a way to make more than one protein from the same gene. By including or skipping different exons, a cell can produce different RNA versions from one starting transcript. This process adds flexibility to gene expression without...

nuclear export of mrna

How mRNA Leaves the Nucleus

Messenger RNA, or mRNA, must move from the nucleus to the cytoplasm before it can be used to make protein. This step is called nuclear export of mRNA. It connects gene expression in the nucleus with protein production in the cytoplasm. During export, the cell selects mRNA molecules that are ready to leave the nucleus. These molecules pass through nuclear pores, which are openings in the nuclear envelope. The process helps keep mRNA transport organized and controlled. Once mRNA reaches the...

transfer rna synthesis

tRNA Genes and RNA Processing

Transfer RNA synthesis begins with transcription of tRNA genes into a primary RNA copy. That first copy is not yet ready to function in protein building. It must be processed before it can become mature transfer RNA. During processing, the cell trims the ends of the RNA and removes extra segments when needed. The transcript also shows that some transfer RNAs carry modified bases. These changes help create the final tRNA structure. Mature transfer RNA folds into a shape that can work in...

ribosomal rna synthesis

Ribosomal RNA and Ribosome Formation

Ribosomal RNA synthesis is part of how cells build ribosomes. Ribosomes are the structures that help make proteins. In this process, cells produce ribosomal RNA, or rRNA, which becomes a key part of the ribosome. The transcript focuses on the making of rRNA and its role in ribosome formation. Ribosomal RNA is not just a message like messenger RNA. It is a structural and functional part of the ribosome itself. Because of that, rRNA synthesis is closely tied to the assembly of ribosomes. This...

the nucleolus

Nucleolus and Ribosome Assembly

The nucleolus is a small structure inside the nucleus. It is the site where ribosome assembly begins. Ribosomes are the cell structures that help make proteins. The nucleolus forms around nucleolar organizer regions, or NORs. These regions contain the genes used to make ribosomal RNA, also called rRNA. Inside the nucleolus, rRNA is produced and combined with proteins to start building ribosomes. Because of this role, the nucleolus is closely tied to protein production in the cell. Its work...

additional subnuclear structures

Subnuclear Bodies and Their Roles

Subnuclear structures are specialized bodies inside the nucleus. They help organize nuclear activity and appear as distinct regions under the microscope. The nucleolus is one of the best-known subnuclear structures. It is the site where ribosomes begin to assemble. Cajal bodies are another nuclear structure. They are linked to the processing and assembly of RNA-related particles. These additional subnuclear structures show that the nucleus is not a uniform space. Instead, it contains...

key terms and concepts

Learn how RNA splicing and alternative splicing help cells remove introns, join exons, and make different proteins from the same gene.

RNA Splicing in Gene Expression | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Virginia  Standards of Learning

HIgh School

BIO.2

BIO.2.d

Alabama Course of Study Science

From Molecules to Organisms: Structures and Processes

9-12.B.1.2

Florida Department of Education

High School

Life Science

SC.912.L.16

SC.912.L.16.6

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

B-LS1-1.

Compounds Essential to Human Function

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lipid-derived-compounds-in-the-human-body

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LS.Bio.1.1

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Catalytically Perfect Enzymes

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introduction-to-mechanisms-of-enzyme-catalysis

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LS.Bio.1.2

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Eukaryotic Compartmentalization

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Prokaryotic Cells

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Cytoplasm

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The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

Endoplasmic Reticulum

Endoplasmic ReticulumThe endoplasmic reticulum (ER) is an extensive network of membranous sacs and tubules in eukaryotic cells, continuous with the outer ...

Ribosomes

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Golgi Apparatus

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Lysosomes

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Peroxisomes

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Introduction to the Cytoskeleton

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overview-of-myosin-structure-and-function

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Gap Junctions

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LS.Bio.1.3

Analyze how the relationship between structure and function supports life processes within organisms.

RNA Splicing in Gene Expression

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