Category: Lab Notes: Molecular Biology

Histone modifications are epigenetic changes that regulate chromatin structure and gene expression. Learn about histone acetylation, methylation, phosphorylation, ubiquitination, their mechanisms, disease associations, and therapeutic significance.

Translation termination is the final stage of protein synthesis in which ribosomes recognize stop codons, recruit release factors, release completed proteins, and recycle their subunits. Learn how UAA, UAG, and UGA stop codons work, how release factors trigger protein release, and how cells control premature termination and translation quality.

RNA is a versatile nucleic acid involved in gene expression, protein synthesis, regulation, and catalysis. Explore RNA structure, nucleotide composition, base pairing, folding, RNA types, processing, and biological functions.

Sm proteins form a conserved structural core of several spliceosomal snRNPs, including U1 snRNP. Learn how Sm proteins interact with snRNA, support snRNP assembly and stability, and contribute to spliceosome formation and RNA splicing.

U1C is a key protein component of U1 snRNP that helps stabilize the complex and support 5′ splice-site recognition during early spliceosome assembly. Learn how U1C works with U1 snRNA and other U1 proteins to initiate RNA splicing and contribute to accurate pre-mRNA processing.

U1-70K is an important protein component of U1 snRNP that supports the early stages of spliceosome assembly and 5′ splice-site recognition. Explore its structure, interactions, role in RNA splicing, and relevance to abnormal splicing.

Mutually exclusive exons are a specialized form of alternative RNA splicing in which a mature RNA transcript contains one exon from a pair or group while excluding the others. This mechanism allows cells to regulate gene expression and generate different RNA transcripts and protein isoforms from the same gene.

U1 snRNA is the RNA component of U1 snRNP and plays a key role in recognizing the 5′ splice site during pre-mRNA splicing. Explore its structure, sequence, RNA-RNA base pairing, spliceosome function, and role in alternative splicing.

U1 snRNP is an early component of the spliceosome that recognizes the 5′ splice site of pre-mRNA. Learn how U1 snRNA and associated proteins help initiate spliceosome assembly, regulate splice-site selection, and support accurate RNA splicing.

The 5′ splice site, also called the donor splice site, marks the beginning of an intron and helps U1 snRNP recognize the correct RNA-splicing boundary. Learn how it works with the spliceosome, branch point, and 3′ splice site during intron removal.

U2AF is an important RNA-splicing factor that helps recognize the 3′ end of many introns. Learn how U2AF65 and U2AF35 interact with the polypyrimidine tract and 3′ splice site and help coordinate spliceosome assembly during pre-mRNA processing.

The polypyrimidine tract is a U- and C-rich sequence near the 3′ end of many introns that helps the spliceosome recognize the 3′ splice site. Learn how it works with the branch point, splicing factors, and other RNA signals to regulate RNA splicing and gene expression.

The branch point is a key sequence region within an intron that contains an important adenosine used during the first reaction of RNA splicing. It helps the spliceosome form the intron lariat and accurately remove introns from pre-mRNA.

Splice-site mutations are genetic variants that disrupt the signals required for accurate RNA splicing. They can cause exon skipping, intron retention, cryptic splice-site activation, abnormal mRNA production, and changes in protein expression.

Cryptic splice sites are normally unused or rarely used splice-like sequences that can become activated when normal splice sites are weakened or when regulatory conditions change. Their activation can alter RNA splicing, mRNA structure, gene expression, and protein production.