Splicing

Definition

Splicing is the process by which introns (non-coding regions) are removed from a pre-mRNA molecule, and the remaining exons (coding regions) are joined together to form a mature, functional mRNA molecule that can be used as a template for protein synthesis during translation.

5 Must Know Facts For Your Next Test

1. Splicing is an essential step in the process of gene expression, as it allows the cell to produce functional proteins from the genetic information encoded in the DNA.
2. The splicing process is carried out by a complex of small nuclear RNAs and proteins called the spliceosome, which recognizes the intron-exon boundaries and catalyzes the removal of the introns.
3. Alternative splicing is a mechanism that allows a single gene to produce multiple different mRNA transcripts, and consequently, multiple different protein isoforms, by selectively including or excluding different exons during the splicing process.
4. Errors in the splicing process can lead to the production of non-functional or aberrant proteins, which can contribute to the development of various genetic diseases and disorders.
5. The study of splicing and its regulation is an active area of research in molecular biology, as it has important implications for understanding gene expression, disease pathogenesis, and the development of targeted therapies.

Review Questions

• Explain the role of splicing in the process of gene expression.
  • Splicing is a crucial step in the gene expression process, as it allows the cell to remove the non-coding introns from the pre-mRNA molecule and join the coding exons together to form a mature, functional mRNA transcript. This mature mRNA can then be used as a template for the synthesis of the corresponding protein during translation. Without splicing, the pre-mRNA would contain both coding and non-coding regions, and the resulting protein would be non-functional or potentially harmful to the cell.
• Describe the mechanism of the splicing process and the role of the spliceosome.
  • The splicing process is carried out by a complex of small nuclear RNAs and proteins called the spliceosome. The spliceosome recognizes the intron-exon boundaries within the pre-mRNA molecule and catalyzes the removal of the introns. Specifically, the spliceosome binds to the 5' and 3' splice sites flanking the intron, and then uses a series of transesterification reactions to excise the intron and join the adjacent exons together. This complex and highly regulated process ensures that the final mRNA molecule contains only the coding regions necessary for protein synthesis.
• Discuss the significance of alternative splicing and its implications for gene expression and disease.
  • Alternative splicing is a mechanism that allows a single gene to produce multiple different mRNA transcripts, and consequently, multiple different protein isoforms, by selectively including or excluding different exons during the splicing process. This process greatly expands the diversity of the proteome and allows cells to fine-tune their gene expression in response to different developmental, physiological, or environmental cues. However, errors in the alternative splicing process can lead to the production of non-functional or aberrant proteins, which can contribute to the development of various genetic diseases and disorders. Understanding the regulation and dysregulation of alternative splicing is an active area of research, as it has important implications for understanding gene expression, disease pathogenesis, and the development of targeted therapies.

Related terms

Introns: Introns are the non-coding regions within a gene that are removed during the splicing process.

Exons:

Exons are the coding regions within a gene that are joined together during the splicing process to form the mature mRNA molecule.

Pre-mRNA: Pre-mRNA is the initial RNA transcript produced during transcription, which contains both introns and exons.