Untitled Notes

Restoration of Glycogen and the Role of CRISPR

Functional restoration of glycogen is significant for patients with certain conditions.
Recent recognition of three scientists has been awarded for their research linked to cystic fibrosis.

CRISPR technology is utilized for editing ammonia levels in the body to prevent severe organ damage, particularly affecting the brain, intestine, and liver.
This condition may lead to death when left untreated.
Example Case: A child born with a metabolic disorder was sustained close to the brink of death until CRISPR-Cas9 targeted therapy was developed.
CRISPR, traditionally a laboratory tool, has advanced to practical patient treatment applications.

Concerns are raised about potential consequences of gene editing, including the possibility of allowing viruses to mutate rapidly within organisms, leading to easier spread.

Historically, RNA may have been the dominant source of genetic information, serving as both the blueprint for protein production and genetic material.
Messenger RNA (mRNA) is one of several types of RNA responsible for conveying genetic information necessary for protein synthesis.

The process of transcription involves converting DNA to RNA, which is remarkably similar in both prokaryotes and eukaryotes.
Key Distinction: Eukaryotes compartmentalize transcription and translation in different cellular sites, while prokaryotes conduct these processes in the same cellular space.

RNA synthesis occurs exclusively from the 5' to 3' direction.
The template strand of DNA serves as a guide for the directionality of RNA transcription.
The sequence of the RNA transcript can be derived from the complementary DNA template strand.
Example: If the RNA sequence generated is CTT ACG, the corresponding DNA template sequence would exhibit complementary base pairing.

The complementary strands of DNA are referred to as template and non-template strands.
The non-template DNA strand shares a similar sequence to the RNA strand, except that thymine (T) bases are present in the DNA while uracil (U) replaces thymine in RNA.

Genes can be transcribed from either strand of DNA, and the specific orientation of transcription based on the gene's properties is crucial.
Promoter Sequences: These are conserved DNA sequences critical for transcription initiation; they are often characterized by TATA boxes, which are specific sequences that bind transcription factors.

The TATA box is a key component of the promoter that is associated with the binding of transcription factors and starts transcription approximately 25 base pairs downstream.

Enhancer sequences play a critical role in transcription efficiency and can be located at various distances from the promoter region.
Enhancers increase transcription efficiency by providing binding sites for transcriptional activator proteins.
Silencer sequences, in contrast, have the opposite effect and decrease transcription.

Transcriptional activator proteins bind to enhancer sequences and facilitate the assembly of a transcription complex.
General transcription factors bind directly to the promoter, including the TATA box.

The TATA box binding protein (TBP) recognizes the TATA box in the promoter and recruits other general transcription factors, initiating the transcription process.
Once the transcriptional activators bind their respective enhancers, they help form a multi-protein complex known as the mediator which interacts with RNA polymerase.
DNA bending is necessary to allow the mediator and RNA polymerase to associate with the promoter.

Once the entire transcription complex is assembled, transcription initiates, leading to the elongation phase where RNA is synthesized based on the DNA template.
The elongation process continues to synthesize RNA in the 5' to 3' direction until transcription is completed, culminating in the full RNA transcript formation.