Lec 3 Flashcards
what is the function of DNA sequences that don’t code proteins?
They function as non-protein RNA molecules.
This differentiates higher eukaryotes from lower eukaryotes. i.e humans from other higher eukaryotes
Define miRNA
miRNA (micro-RNA) are endogenous single stranded (ss) regulatory RNA molecules
size of miRNA?
They are roughly 2023 nucleotides in length and usually have uridine at their 5’ end
what are miRNA encoded by?
they are encoded by genes in genomes of all multicellular eukaryotes and some unicellular eukaryotes
Around ___ miRNA genes have been identified
5000
Size of LncRNAs
long non-coding RNAs are >200 nucleotides in length
where are LncRNAs located
within the nucleus or cystoplasm
true or false:
LncRNAs may or may not be polyadenylated
true
LncRNAs are often transcribed from?
from either strand within a protein-coding locus
Mammlian genomes encode ____ LncRNAs
more than 3300 LncRNAS
Define pseudogenes
They are non-coding DNA sequences
They arise by coping the parent gene by:
- duplication or
- retrotransposition
Define retrotransposition
.
A/an ____ of the pseudogene and a/an ___ of its parent gene can then form a ___
An antisense transcript of the pseudogene and an mRNA transcript of its parent gene can then form a double-stranded RNA (dsRNA)
Distinguish “sense RNA” from “antisense RNA”
sense RNA= mRNA with the coding information of the gene-encoded polypeptide
antisense RNA = complementary RNA to the mRNA
___ was the first founding member of the miRNA family where it ___ the protein ___ in ___
Lin-4 was the first founding member of the miRNA family where it downregulates the protein lin-14 in Celegans
__% of mammalian miRNA genes are located in ___
30% of mammalian miRNA genes are located in intergenic regions (between protein coding regions)
Define intergenic regions
between protein coding regions
___ is transcribed but __ are not translated into ____(non-coding RNA)
DNA is transcribed but miRNAs are not translated into protein (non-coding RNA)
Many LncRNAs are associated with ___ and guide
in terms of chromatin
Many LncRNAs are associated with chromatin-modifying complexes and guide chromatin-modifying complexes to specific genomic loci to regulate gene expression
___ of LncRNAs expressed in various cell types are bound by ____
20% of LncRNAs are expressed in various cell types are bound by polycomb repressive complex 2.
