Term
| Two consequences of reduced or abnormal protein levels in thalassemia |
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Definition
| loss of overall oxygen carrying capacity and abnormal aggregation leading to cell destruction (alpha-4 or beta-4) |
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Term
| Thalassemia Major (beta-null) (Cooley's anemia) symptoms |
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Definition
Hemolytic anemia within 1 year of birth
Bone deformities in the face/enlarged spleen
Fatigue
Growth failure
Shortness of breath
Yellow skin (jaundice) |
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Term
| thalassemia minor (beta-+) symptoms |
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Definition
| No obvious symptoms unless living at high altitude or engaging in extreme exertion |
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Term
| Steps of transcription initiation and elongation |
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Definition
| Binding of RNA Polymerase, Separation of DNA, Binding of first nucleotide selected by base pairing, binding of second nucleotide and first internucleotide linkage. ppp remains at 5' end, and pp splits from second nucleotide, third nucleotide added, process continues |
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Term
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Definition
| general class of proteins that can affect transcriptional efficiency by binding at particular sequences with high specificity (activators and repressors) |
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Term
| Prokaryotic Promoter Recognition |
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Definition
| Sigma protein binds to RNA Pol holoenzyme. Pol binds to promoter region and unwinds DNA. Sigma leaves and core enzyme begins transcription |
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Term
| Two types of transcription termination in prokaryotes |
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Definition
| rho-dependent and rho-independent |
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Term
| Rho-dependent termination |
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Definition
| helicase protein called rho binds to the RNA-DNA duplex at a point downstream of the translation STOP signal, and denatures the RNA-DNA duplex owing to its ATP-dependent unwinding activity |
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Term
| Rho-independent termination |
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Definition
| A specific G/C-rich sequence signal downstream of the translation STOP signal causes the RNA polymerase to stall out over an immediately following A/T rich sequence. The DNA duplex is re-established, expelling the RNA molecule from the transcription bubble |
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Term
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Definition
| allows several genes to be expressed simultaneously (“coordinate expression”) from a single promoter via a single mRNA |
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Term
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Definition
| sequence in mRNA that precedes each distinct coding region where ribosome binds. only occur in prokaryotes |
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Term
| Promoter-proximal elements |
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Definition
| CAAT box (-110) and GC-rich regions (-40) |
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Term
| Core promoter (binds pol II) |
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Definition
| TATA box (-30-20) and Initiator. |
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Term
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Definition
| In nucleolus, creates cellular transcripts for 18S, 5.8S and 28S rRNA |
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Term
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Definition
| Located in nucleoplasm, creates mRNA and other non-coding RNA |
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Term
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Definition
| Located in nucleoplasm, creates tRNA and 5S rRNA |
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Term
| Eukaryotic pre-initiation complex |
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Definition
| TATA Binding Protein (TBP) is part of Pol II basal transcription factor (TFII) complex called TFIID. Bind to TATA box and Initiator |
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Term
| 3 steps of mRNA processing |
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Definition
| capping, polyadenylation, splicing |
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Term
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Definition
A specific “capping” enzyme adds GTP to the 5’ end of mRNA in a unique 5’-5’ triphosphate linkage. Specific methylases modify the nucleotides post-transcriptionally at the 2’-OH and N-7.
Capping occurs very soon after pol II has initiated transcription. It stabilizes the mRNA against nuclease degradation from the 5’ end and is essential for eukaryotic mRNA translation initiation |
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Term
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Definition
Pre-mRNA cleavage site is situated just a few nucleotides 3’ of a AAUAAA polyadenylation recognition signal.
A non-templated chain of 100-200 A nucleotides is added to the 3’-OH end by poly(A) polymerase and ATP. Polyadenylation stabilizes mRNA against nuclease degradation from the 3’-end and plays an important role in translation initiation |
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Term
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Definition
| All 5’ splice junctions contain an invariant GU at the 5’-end of the intron. All 3’ splice junctions contain an invariant AG at the 3’-end of the intron. Each invariant splice junction is surrounded by short consensus (i.e., not invariant) sequences that contribute to the efficiency of splicing. An adenine (A) base approx. 30 nt upstream of the 3’ splice site plays an essential role |
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Term
| Basic mechanism of splicing |
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Definition
| snRNPs are attracted to their sites of interaction on the precursor mRNA by complementary base-pairing between their snRNA component and short stretches of local mRNA sequence. They help fold the precursor mRNA into the appropriate structure and catalyze the breaking and reformation of 5’-3’ phosphodiester linkages. The essential A base forms an intron lariat via 2’, 3’ and 5’ phosphodiester linkages. The net energy is zero b/c there is a breaking of a phosphodiester linkage and the creation of a new one |
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Term
| How cryptic splice junction can elicit thalassemia major |
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Definition
Mutation in invariant AG leads to a “cryptic” splice site within intron 2 now being used (conforms reasonably well to a consensus acceptor).
A non-functional b-globin protein is produced (contains sequences derived from intron 2) leading to a bo-thalassemia condition |
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