Lecture 8 Non-coding RNA Flashcards
Learning Objectives
The first non-coding RNA !
Ribosomal RNA – the most abundant RNA in cells !
Total RNA isolated from human cells
RNA2 band shows is the better method to help distinguish the RNA subunits
Different types of cellular RNAs
need to study these and know all their differences
Small nuclear RNAs – snRNAs
their function is to coordinate splicing
Small nucleolar RNAs – snoRNAs
Different types of cellular RNAs
Small non-coding RNAs affect translation or decay
of mRNAs in the cytoplasm
The difference between miRNAs and
siRNAs
miRNAs only partially hybridize
siRNAs completely base pair
How are miRNAs/siRNAs generated in cells?
Developmental defects in inducible Dicer
gene knock-outs
miRNAs and disease
miRNAs expression signatures are linked to cancer
Different types of cellular RNAs
Long non-coding RNAs (lncRNAs)
Functions of lncRNAs
Nuclear lncRNAs control chromatin
structure/transcription in cis or trans
Example: XIST –a lncRNA that controls
mammalian dosage compensation
XIST: X inactivation specific transcript
Cytoplasmic lncRNA can have diverse functions
Example: The cytoplasmic lncRNA NORAD acts as
“decoy” for RNA-binding proteins
Circular RNAs (circRNAs) can act as
decoys for miRNAs/RBPs
Summary
Supplement 1: HOTAIR lincRNA represses
transcription in trans
Supplement 2: XIST likely functions by a “spreading” mechanism at
“chromosome entry sites”
