Term
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Definition
Target: Gene
Result: RNA
- Major enzyme is RNA polymerase |
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Term
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Definition
multi-protein enzyme
mRNA is a temporary copy of a gene
- Uses: ATP, UTP, CTP, GTP |
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Definition
| RNA will H bond with itself; RNA:RNA structures are very stable. Secondary structures might be expected to interfere with translation - used for genetic control |
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Term
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Definition
RNA POL is made of alpha (2), beta, beta' proteins (core enzyme).
- Add one of several different sigma factors to make functional holoenzyme.
- Recognizes promoter regions upstream of start site.
- Melts DNA locally and starts transcription process |
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Term
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Definition
Two methods in bacteria:
1) Rho independent termination: depends on a folding of the RNA transcript into a stem-loop which disrupts RNA-DNA pairing, and how polymerase binds the RNA transcript.
2) Rho dependent termination, a protein binds the nascent transcript and stops the RNA polymerase (bumps RNA POL off DNA strand) |
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Term
| RNA Polymerase Inhibitors |
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Definition
Rifampin and rifapentine are antibiotics based on Rifamycin.
-Inhibit transcription in bacteria by binding to the beta-subunit of the bacterial RNA polymerase
-Cordycepin is an adenosine analog: stops RNA elongation, works against eucaryotes as well.
- Actinomycin D used in cancer treatments |
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Term
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Definition
variety of fxns: rRNA, tRNA
-many involved in translation
Long noncoding RNAs (lncRNA) are implicated in transcription control in the nucleus, even on a multigene level
-Xist: controls X-chromosome inactivation in females
-HOTAIR: controls some chromatin structure through histones.
- Also, post-transcriptional control, epigenetics |
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Term
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Definition
miRNA related to small interfering RNA
-small; 22 nucleotides
-bind to target RNA, making it ds and shutting it off
-Often bind near the poly-A tail, destabilizing the transcript
-Possible therapeutic agents |
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Term
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Definition
Nucleosome = DNA + histone
DNA is unwound = available for binding and expression.
Amino termini of histones are covalently modified to make them neutrally charged, which leads to DNA access
Recruits transcription factors
Reversed to turn off expression |
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Term
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Definition
Sites are less defined, spread over large area
Enhancer elements can be located far away
Tissue type determines which additional factors are needed for expression of that specific gene |
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Term
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Definition
Accessory proteins (transcription factors) help POL II to form an active transcription complex with DNA.
Elongation factors suppress pausing by the polymerase, and help coordinate post-transcriptional processing of the RNA.
Mediator complex associates with the RNA Pol II to convey regulatory information from activators and repressor proteins |
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Term
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Definition
After termination, but before leaving the nucleus, receives special nucleotide sequences at the 3' and 5' ends.
1) 5' capping
2) poly(A) tail
3) Splicing |
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Term
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Definition
5' end of the eucaryotic mRNA acquires a "cap" molecule
- First modification of the message (after production of only 25 nucleotides)
- 7-methylguanosine connected via 5' to 5' triphosphate
- 5' end already has a triphosphate |
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Term
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Definition
Poly(A) tailing, usually a few hundred A residues
- Added to the 3' end after transcription is done.
- PAP - poly(A) polymerase and polyA binding protein
- Responds to sequences on the mRNA
- CPSF: cleavage and polyadenylation specificity factor |
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Term
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Definition
Removal of introns in order to create the translatable mRNA
- Exons have translatable sequences
- Specific recognition nucleotides within the introns
- It is not unusual for the intron segments to be far larger than the exon segments
- Uses ribozymes: RNA molecules which have a catalytic (enzymatic) function. More common than originally thought. |
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Term
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Definition
Uses five snRNA molecules (U1,2,4,5,6)
-small,nuclear RNA
-Associated with seven (or more) proteins to make snRNPs ("snurps")
-Critical step is basepairing of the snRNA with the exon-intron junction |
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