Simple but Mighty
This detachable subunit of prokaryotic RNA polymerase is responsible for recognizing promoter sequences such as the −10 and −35 elements.
What is the sigma factor?
This term describes a cluster of bacterial genes transcribed as a single mRNA under the control of one promoter.
What is an operon?
This eukaryotic RNA polymerase is responsible for synthesizing mRNA and many noncoding RNAs, and requires a full suite of general transcription factors to initiate transcription.
What is RNA polymerase II?
This protein octamer, composed of two copies each of H2A, H2B, H3, and H4, forms the core around which DNA is wrapped in eukaryotic chromatin.
What is the nucleosome core particle? or what is a Histone?
These short DNA sequences in promoters or enhancers bind specific transcription factors to regulate gene expression in response to hormones, stress, or metabolic signals.
What are response elements?
This core enzyme subunit provides the catalytic activity for RNA synthesis and contains the active‑site aspartate residues that coordinate Mg²⁺.
What is the β subunit?
This DNA sequence, located between the promoter and structural genes, is the binding site for regulatory proteins that control operon transcription.
What is the operator?
This DNA element, located upstream of many protein‑coding genes, binds TFIID through its TBP subunit to help position RNA polymerase II at the start site.
What is the TATA box?
This positively charged histone tail modification generally loosens chromatin structure and increases transcriptional accessibility.
What is acetylation?
This response element binds a receptor that dimerizes upon cortisol binding, allowing the complex to activate genes involved in stress adaptation.
What is the glucocorticoid response element (GRE)?
This region of the promoter, located around 10 bases upstream of the transcription start site, is rich in A and T and helps RNA polymerase melt the DNA duplex.
What is the Pribnow box?
This type of operon, exemplified by the lac operon, is normally “off” but can be turned “on” when an inducer binds to its repressor.
What is an inducible operon?
This C‑terminal domain of RNA polymerase II becomes heavily phosphorylated during transcription initiation and elongation, coordinating RNA processing events.
What is the CTD (C‑terminal domain)?
This higher‑order chromatin structure describes DNA that is tightly packed, transcriptionally silent, and often enriched in H3K9 methylation.
What is heterochromatin?
This response element is recognized by a transcription factor that activates antioxidant and detoxification genes during oxidative stress.
What is the antioxidant response element (ARE)?
This protein binds to the rut site on RNA and uses ATP hydrolysis to terminate transcription in one of the two major prokaryotic termination pathways.
What is Rho?
This type of operon, exemplified by the trp operon, is normally “on” but can be shut down when its end‑product binds to the repressor.
What is a repressible operon?
This RNA processing event occurs co‑transcriptionally and protects the 5′ end of the nascent transcript while aiding in ribosome recruitment.
What is 5′ capping?
This ATP‑dependent process shifts or evicts histones to expose promoter DNA, allowing RNA polymerase to access the template for transcription.
What is chromatin remodeling?
This DNA element binds CREB when it is phosphorylated by PKA, linking cAMP signaling to transcriptional activation.
What is the cAMP response element (CRE)?
This subunit of prokaryotic RNA polymerase is required for enzyme assembly and binds upstream promoter elements such as the UP‑element to enhance transcription initiation.
What is the alpha subunit?
This regulatory mechanism, found in some amino acid biosynthetic operons, fine‑tunes transcription by coupling translation speed to RNA secondary structure formation.
What is attenuation?
This multi‑subunit complex acts as a bridge between gene‑specific transcription activators and the general transcription machinery, helping regulate RNA polymerase II activity.
What is the Mediator complex?
These enzymes remove acetyl groups from lysine residues on histone tails, promoting chromatin compaction and generally reducing transcriptional activity.
What are histone deacetylases (HDACs)?
This response element is activated by heat shock factor (HSF), which trimerizes and binds DNA to induce chaperone expression during proteotoxic stress.
What is the heat shock response element (HSE)?