Transcript Non-Coding RNA

Non-Coding
RNA
Kirsten Dimmler
Non-Coding RNA
Kirsten Dimmler
What is Non-Coding RNA?

mRNA accounts for only 1-5% of all cellular RNA

Only 2% of genomic DNA codes for proteins

What is the rest? Junk DNA?
The Human Genome Project and ENCODE
The Human Genome
Project
• Generated 15
terabytes of raw data
• Revealed that only 2%
of genomic DNA codes
for proteins
• Labeled the rest “Junk
DNA”
The Encyclopedia of DNA Elements (ENCODE)
• World-wide consortium of research groups
founded in 2003 by the NHGRI
• Goal to determine the function of junk DNA
• Ultimately found that junk DNA codes for
RNA gene products of differing functions.
• These RNA would come to be known as noncoding RNA.
Categories of Non-Coding RNA
Name
Size (nucelotides)
Function
Transfer RNA (tRNA)
76-90
Transfers amino acids to
ribosomes during protein
synthesis
Ribosomal RNA (rRNA)
Variable
Catalyzes peptide bond
formation during protein
synthesis
Small Nucelar RNA
(snRNA)
60-150
Aid in regulation of
transcription factors, RNA
polymerase II, maintain
telomeres
Small Nucleolar RNA
(snoRNA)
60-150
Guide epigenetic
modifications of pre-rRNA
MicroRNA (miRNA)
21-24
Bind complimentarily to mRNA
to effectively silence gene
expression
Piwi-interacting RNA
(piRNA)
26-31
Epigenetic and posttranscriptional gene silencing
of retrotransposons
Small Interfering RNA
(siRNA)
20-25
Uses the RNA interference
pathway to regulate gene
expression
Structure
RNA Interference (RNAi) and Small
Interfering RNA (siRNA)

RNAi – The process by which RNA
inhibits gene expression

siRNA inhibits gene expression by posttranscriptional degradation of mRNA
MicroRNA (miRNA) and Gene Regulation

Bind complimentarily to mRNA within
the 3’ untranslated region

Many mechanisms for gene regulation

(A) Degredation of mRNA

(B) Blocking of initiation

(C) Translocation to processing bodies
Disease
Many diseases caused by
dysregulation of ncRNA,
especially miRNA
Medicine

Potential Therapies for:


Dysregulation of miRNA

Inhibit miRNA function: Introduction of antisense
oligonucleotides

Restore miRNA function: Enoxacin to enhance RNAi,
molecules to release epigenetic silencing of tumor
suppressors
Viral Infections


RNAi mediated by miRNA and siRNA inhibits viral
replication
Bacterial Infections

Ribocil is a riboswitch antibiotic that inhibits bacteria
from producing Vitamin B2
Roboswitches
Ribocil
References


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doi:10.1038/nrg3074

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
Jackson, R. J., & Standart, N. (2007). How Do
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
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
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
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
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
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
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
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