What causes alternative splicing?

What causes alternative splicing?

Alternative splicing is the process of selecting different combinations of splice sites within a messenger RNA precursor (pre-mRNA) to produce variably spliced mRNAs. These multiple mRNAs can encode proteins that vary in their sequence and activity, and yet arise from a single gene.

Can you describe the process of transcription?

Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA). The newly formed mRNA copies of the gene then serve as blueprints for protein synthesis during the process of translation.

What is the primary purpose of RNA splicing?

RNA splicing is a process that removes the intervening, non-coding sequences of genes (introns) from pre-mRNA and joins the protein-coding sequences (exons) together in order to enable translation of mRNA into a protein.

What happens during RNA splicing?

In splicing, some sections of the RNA transcript (introns) are removed, and the remaining sections (exons) are stuck back together. Some genes can be alternatively spliced, leading to the production of different mature mRNA molecules from the same initial transcript.

What regulates alternative splicing?

Splicing is regulated by trans-acting proteins (repressors and activators) and corresponding cis-acting regulatory sites (silencers and enhancers) on the pre-mRNA. However, as part of the complexity of alternative splicing, it is noted that the effects of a splicing factor are frequently position-dependent.

What is significant about alternative RNA splicing?

Alternative splicing of RNA is a crucial process for changing the genomic instructions into functional proteins. It plays a critical role in the regulation of gene expression and protein diversity in a variety of eukaryotes. In humans, approximately 95% of multi-exon genes undergo alternative splicing.

What is DNA transcription and translation?

The process by which DNA is copied to RNA is called transcription, and that by which RNA is used to produce proteins is called translation.

What happens to DNA molecule after transcription?

After the transcription of DNA to mRNA is complete, translation — or the reading of these mRNAs to make proteins — begins. Recall that mRNA molecules are single stranded, and the order of their bases — A, U, C, and G — is complementary to that in specific portions of the cell’s DNA.

Why is RNA splicing important and steps of RNA splicing?

The process of RNA splicing involves the removal of non-coding sequences or introns and joining of the coding sequences or exons. In eukaryotic cells, RNA splicing is crucial as it ensures that an immature RNA molecule is converted into a mature molecule that can then be translated into proteins.

What molecules are involved in RNA splicing?

Splicing is catalyzed by the spliceosome, a large RNA-protein complex composed of five small nuclear ribonucleoproteins (snRNPs). Assembly and activity of the spliceosome occurs during transcription of the pre-mRNA. The RNA components of snRNPs interact with the intron and are involved in catalysis.

How does alternative splicing control gene expression?

Alternative splicing can regulate protein composition by changing the coding content between isoforms of the same gene. As a consequence, AS contributes to increased protein diversity and, ultimately, cellular and functional complexity, without increasing the size of a eukaryotic organism’s genome (Stamm et al., 2005).

Who regulate the splicing process?

The SR protein family and hnRNPs are universal splicing regulators. The key RBP families involved in splicing regulation are the serine/arginine-rich proteins (SR proteins) [10, 55] and heterogeneous nuclear ribonucleoproteins (hnRNPs) [11, 56].

Bagaimana cara transkripsi DNA?

Adapun arah transkripsi adalah dari 5′ ke 3′. Adapun substratnya adalah nukleosida trifosfat yaitu ATP, CTP, UTP, dan GTP. Proses transkripsi DNA oleh RNA polimerase. (A) RNA polimerase (warna biru muda) berjalan sepanjang DNA, membuka struktur heliks DNA.

Apakah transkripsi merupakan sintesis RNA?

Transkripsi adalah sintesis RNA yang diarahkan oleh DNA. Sintesis RNA pada cetakan DNA dikatalis oleh enzim RNA polimerase. Sintesis ini mengikuti aturan pemasangan basa yang sama seperti replikasi DNA , terkecuali bahwa pada RNA, urasil menggantikan timin.

Apakah kesalahan transkripsi DNA terjadi pada replikasi DNA?

Lagi pula, kesalahan transkripsi DNA tidak seberat kesalahan yang terjadi pada replikasi DNA. Secara struktur juga ternyata sangat berbeda. Walaupun sama-sama mengandung ion Mg 2+ di situs katalitiknya, dari pembandingan kristalografi, bentuk kedua enzim itu tidak terkait satu sama lainnya. Di bawah ini adalah skema struktur RNA polimerase.

Bagaimana proses transkripsi protein dimulai?

Tahap proses transkripsi sintesis protein dapat dibagi lagi menjadi tiga tahap, yaitu iniasi, elongasi, dan terminasi. Tahap ini diawali oleh melekatnya enzim RNA polimerase pada pita DNA pada titik awal. Pita DNA akan terbuka, akibatnya basa nitrogen pada pita tersebut menjadi bebas.