Introduction (Moll)

Central Dogma of molecular biology

The framework explaining the flow of genetic information from DNA to RNA and then to protein synthesis, describing the processes of transcription and translation

Which organisms defy the Central Dogma?

Viruses

Which enzymes ensure that viruses can synthesize DNA from RNA?

Reverse transcriptases

Co-transcriptional protein synthesis

Process of simultaneous transcription and translation of DNA in procaryotes

Codirectional replication-transcription conflict in bacteria

A collision between the Replisome and RNA-Polymerase, when the faster Replisome moves behind the RNA-Polymerase

Head-on replication-transcription conflict in bacteria

A collision between a Replisome and RNA-Polymerase, when they’re moving in the opposite directions

Genome size of E. coli

4.64 million basepairs, encoding around 4500 genes

Operon

A functioning unit of genomic DNA that contains a cluster of genes under the control of a single promoter, allowing coordinated gene expression.

Polycistronic mRNA

mRNA, transcribed from a single operon, that carries the genetic information to encode multiple genes

Orphan genes

Genes that are not associated with any known operon and do not have homologs in other species. They often play unique roles in specialized cell adaptations and responses

Monocistronic mRNA

mRNA that encodes a single protein product from a single gene

What is 5’ Triphosphate?

Three phosphate groups at the 5’ end of the mRNA that trigger the immune response to foreign RNA

What is a 5’ UTR?

5’ Untranslated Region that is located upstream of a start-codon

What is a sequence of the Shine-Dalgarno Sequence?

GGAGG

The role of the Shine-Dalgarno Sequence

It’s located in the 5’ UTR and serves as a docking site for the 16S subunit of a ribosome

What is ORF?

Open Reading Frame, a sequence of DNA that carries the gene(s)

The sequence of the Start-Codon

AUG, coding for Methionine

The sequence of the Stop-Codons

UAG, UAA, UGA

What is RNA-P?

RNA-Polymerase

What is RNA-P structurally?

A holoenzyme

How many subunits are there in the core enzyme of RNA-P?

2 alpha subunits, beta and beta-prime subunits and an omega subunit

What ion binds the core enzyme of RNA-P?

Mg²⁺

The role of alpha-subunits in the RNA-P

They recognize the promoter and act as targets for transcription activator proteins

The role of beta and beta-prime subunits in RNA-P

They form the catalytic site, responsible for the RNA-synthesis

The role of the omega-subunit in the RNA-P

The omega-subunit stabilizes the RNA polymerase complex and assists in the proper assembly of the enzyme

What does holoenzyme RNA-P consist of?

A core enzyme and sigma-factors

What are sigma-factors in RNA-P responsible for?

They recognize the appropriate promoter DNA-sequence

What is a Consensus sequence?

It’s a DNA/RNA-sequence that represents aligned, related sequences defined by the most common nucleotides at each position

What is DNA-footprinting?

It’s a molecular biology technique used to identify the specific binding sites of proteins on DNA by revealing regions protected from cleavage

What is abbreviated in EMSA?

Electrophoretic Mobility Shift Assay

What is EMSA?

A molecular biology technique, used to study protein-DNA interactions by analyzing the shift in mobility of DNA during electrophoresis

What is a 3’ UTR?

The 3' untranslated region is a section of mRNA that follows the coding sequence