BIO - TERMS - RNA Flashcards
7SL RNA
A component of the signal recognition particle and the grandfather of the Alu sequences.
alternative RNA splicing
Production of different RNAs from the same gene by splicing the transcript in different ways.
Antisense RNA
RNA that is complementary to the pre-mRNA or mRNA produced from a gene.
Defective interfering RNAs
Subgenomic RNAs that replicate more rapidly than full-length RNA and therefore compete for the components of the RNA synthesis machinery and interfere with the replication of full-length RNAs. (Chapter 6)
Functional RNAs
An alternative name for small RNAs.
Guide RNAs
RNA molecules that contain sequences that function as templates during RNA editing.
ncRNA (noncoding RNA)
Any RNA that does not encode instructions for a protein product.
noncoding RNA
An RNA molecule that is the final product of a gene and does not code for protein. These RNAs serve as enzymatic, structural, and regulatory components for a wide variety of processes in the cell.
piRNAs (piwi-interacting RNAs)
A class of small noncoding RNAs made in the germ line that, in complex with Piwi proteins, keep in check the movement of transposable elements by transcriptionally silencing transposon genes and destroying RNAs produced by them.
RNA exosome
A multisubunit complex involved in processing and editing of RNA.
RNA processing
The series of co- or posttranscriptional covalent modifications that produce mature mRNAs from primary transcripts. (Chapter 10)
RNA processing control
Regulation by a cell of gene expression by controlling the processing of RNA transcripts, which includes their splicing.
RNA pseudoknot
An RNA secondary structure formed when a single-stranded loop region base pairs with a complementary sequence outside the loop. (Chapter 6)
RNA transport and localization control
Regulation by a cell of gene expression by selecting which completed mRNAs are exported from the nucleus to the cytosol and determining where in the cytosol they are localized.
RNA world
Hypothesis that early life on Earth was based primarily on RNA molecules that both stored genetic information and catalyzed biochemical reactions.
RNA-dependent RNA polymerase
The protein assembly required to carry out RNA synthesis. (Chapter 6)
RNA-seq
Sequencing the entire repertoire of RNA from a cell or tissue; also known as deep RNA sequencing.
ribosomal RNA (rRNA) sequencing
Determination of the order of nucleotide bases in rRNA.
RNAi
RNA interference; stops gene expression at transcription by using a short interfering RNA to make double-stranded RNA.
Sense RNA
A primary transcript or mRNA that contains a coding region (contiguous sequence of codons) that is translated to produce a polypeptide.
Short interfering RNA (siRNA)
Double-stranded RNA molecules 21–28 base pairs long that mediate the phenomenon of RNA interference; also known as microRNA molecules.
Single guide RNA (sgRNA)
An RNA molecule able to guide a targeting endonuclease to a specific sequence in a genome.
single-stranded RNA (ssRNA)
Normally confined to the nucleus and cytoplasm, this normal molecular form serves as a ligand for TLR-7, TLR-8, and TLR-9 when it is present in endosomes, as during parts of a viral life cycle.
small hairpin RNA (shRNA)
A type of RNA that functions in a manner similar to miRNA. It is used in experiments where it is introduced into cells using a vector, such as a plasmid or virus. It can either block translation or lead to mRNA degradation.
small RNAs
A type of RNA that has a variety of functions within the cell, including silencing transcription and catalyzing chemical modiications of other RNA molecules.
TFIIX (Transcription Factor X for RNA polymerase II)
A protein required for the initiation of transcription by RNA polymerase II in eukaryotes; X represents any one of several different factors designated A through F.
amanitin
A polypeptide toxin produced by Amanita spp., inhibits RNA polymerase.
Ambisense
Producing mRNAs from both ( - ) strand genomic RNA and the complementary ( + ) strand; refers to viral genomes. (Chapter 6)
Cap
A methylguanosine-containing structure at the 5′ end of eukaryotic messenger RNA.
Cap snatching
Cleavage of cellular RNA polymerase II transcripts by a viral endonuclease to produce capped primers for viral mRNA synthesis. (Chapters 6 and 10)
cellular differentiation
The process in which a precursor cell becomes specialized to carry out a particular function, by acquiring a new complement of proteins and RNA.
cleavage stimulation factor
A multi-subunit protein complex involved in the modification of the 3ʹ end of pre-messenger RNA for the addition of the polyadenine (polyA) tail.
conditional mutation
Mutation that changes a protein or RNA molecule so that its function is altered only under some conditions, such as at an unusually high or unusually low temperature.
ethambutol
A synthetic antimicrobial agent that interferes with the synthesis of RNA.
exosome
Large protein complex with an interior rich in 3′-to-5′ RNA exonucleases; degrades RNA molecules to produce ribonucleotides.
gene silencing
A mechanism to inhibit gene expression. See RNAi.
general transcription factor
Any of the proteins whose assembly at all promoters of a given type is required for the binding and activation of RNA polymerase and the initiation of transcription.
Intrinsic cellular defenses
The conserved cellular programs that respond to various stresses, such as starvation, irradiation, and infection; intrinsic defenses include apoptosis, autophagy, and RNA interference. (Chapters 2 and 3)
iron-responsive element-binding protein (IREP)
A protein involved in iron metabolism that interacts with messenger RNA to either inhibit translation of iron storage proteins (e.g., ferritin) or enhance the stability of iron transporters such as transferrin receptors. IREPs are active proteins in iron deficiency.
Latency-associated transcript
RNA produced specifi cally during a latent infection by herpes simplex virus. (Chapter 5)
LGP2
A member of the RLR family, it cooperates with RIG-I and MDA-5 in the recognition of viral RNA.
lymphatic vessels, lymphatics
Thin-walled vessels that carry lymph. lymphoblast A lymphocyte that has enlarged after activation and has increased its rate of RNA and protein synthesis, but is not yet fully differentiated.
MDA-5 (melanoma differentiation-associated 5, also helicard)
This protein contains an RNA helicase-like domain similar to RIG-I, and senses double-stranded RNA for detection of intracellular viral infections.
Northern blot
The transfer of RNA molecules from an electrophoretic gel to a cellulose or nylon membrane by capillary action.
Northern blotting
A method for the identification of RNA after gel electrophoresis, using a probe.
Nucleolar Organizer (NO)
A chromosomal segment containing genes that control the synthesis of ribosomal RNA, located at the secondary constriction of some chromosomes.
Operon model
The negative control mechanism proposed by Jacob and Monod in 1961 to explain the coordinate regulation of cotranscribed sets of structural genes. The mechanism involves a regulator gene encoding a repressor that controls transcription of the set of genes by binding to an operator region and blocking transcription by RNA polymerase.
polymerase stalling
The halting of RNA polymerase during the transcription of a gene at locations within the gene locus, known to be a regulated process, and involved in mechanisms of isotype switching.
post-transcriptional modification
The process by which heterogeneous nuclear RNA is changed into mature messenger RNA.
Processed pseudogenes
Nonviral retroposons derived by the reverse transcription of a messenger RNA.
Promoter occlusion
The mechanism by which access to a promoter is blocked by passage of a transcribing RNA polymerase. (Chapter 8)
quasi-species
The different genetic forms of certain RNA viruses that are formed by mutation during the course of an infection.
Reassortment
The exchange of entire RNA molecules between genetically related viruses with segmented genomes. (Chapters 3 and 6)
Recognition sequence (-35 sequence)
A nucleotide sequence (consensus TTGACA) in prokaryotic promoters to which the sigma factor of RNA polymerase binds during the initiation of transcription.
regulated nuclear transport
Mechanisms controlling export of mRNAs from the nucleus to the cytosol that can be used to regulate gene expression. Also includes the selective import of proteins and RNA molecules into the nucleus.
Rifampicin
An inhibitor of bacterial RNA polymerase.
RIG-I-like receptors (RLRs)
A small family of intracellular viral sensors that use a carboxy terminal RNA helicase-like domain in detection of various forms of viral RNA. These signal through MAVS to activate antiviral immunity. Examples include RIG-I, MDA-5, and LGP2.
rRNA gene
Gene that specifies a ribosomal RNA (rRNA).
SELEX
A method for rapid experimental identification of nucleic acid sequences (usually RNA) that have particular catalytic or ligand-binding properties.
sense strand (+ strand)
Viral RNA that can act as mRNA.
Sigma factor
The subunit of prokaryotic RNA polymerases that is responsible for the initiation of transcription at specific initiation sequences.
Spt5
A transcription elongation factor required for isotype switching in B cells that functions in associatioin with RNA polymerase to enable recruitment of AID to its targets in the genome.
TLR-3
Endosomal Toll-like receptor that recognizes double-stranded viral RNA.
TLR-7
Endosomal Toll-like receptor that recognizes single-stranded viral RNA.
TLR-8
Endosomal Toll-like receptor that recognizes single-stranded viral RNA.
Transcript
The RNA molecule produced by transcription of a gene.
Transcriptional antiterminator
A protein that prevents RNA polymerase from terminating transcription at specific transcription– termination sequences.
transcuprin
A plasma protein that transports copper. transfer RNA (tRNA) The RNA found in the cytoplasm that is responsible for bringing specific amino acids to the ribosomes in the process of protein synthesis.
α-Amanitin
A mushroom poison that inhibits RNA polymerase II.
σ
(1) See superhelical density. (2) A subunit of the bacterial RNA polymerase that confers specifity for certain promoters; usually designated by a superscript indicating its size (for example, σ70 has a molecular weight of 70,000).
σ Subunit
A subunit of bacterial RNA polymerase required for promoter recognition.
3’ untranslated region
The region of an mRNA downstream of the translation termination codon. (Chapter 11)
5’ untranslated region
The region of an mRNA upstream of the translation initiation codon. (Chapter 11)
5′-cap (mRNA)
The 7-methy guanosine cap that is added to most eukaryotic mRNAs posttranscriptionally.
Alternative splicing
Splicing of different combinations of exons in a pre-mRNA, generally leading to synthesis of mRNAs with different protein-coding sequences. (Chapter 10)
Aminoacyl (A) site
The ribosome binding site that contains the incoming aminoacyl-tRNA.
Cap structure
The m 7 G linked via a 5‘–5’ phosphodiester bond to the 5’ ends of the majority of viral and cellular mRNAs made in eukaryotic cells. (Chapter 11)
Constitutive transport elements
Sequences in certain unspliced viral mRNAs that direct export from the nucleus by host cell proteins. (Chapter 10)
defective ribosomal products (DRiPs)
Peptides translated from introns in improperly spliced mRNAs, translations of frameshifts, or improperly folded proteins, which are recognized and tagged by ubiquitin for degradation by the proteasome.
Exit (E) site
The ribosome binding site that contains the free tRNA prior to its release.
initiation complex
A complex of a ribosome with an mRNA and the initiating Met-tRNAMet or fMet-tRNAfMet, ready for the elongation steps.
intermembrane space
Compartment of mitochondrion between by the outer and inner mitochondrial membranes. internal ribosome entry site (IRES) Specific site in a eukaryotic mRNA, other than at the 5′ end, at which translation can be initiated.
Internal ribosome entry site
(IRES) An internal binding site for 40S ribosomal subunits and initiation of translation present in some viral and few cellular mRNAs. (Chapter 11)
Kozak’s rules
The sequence requirements—5′-GCC(A or G) CCAUGG-3′—for optimal initiation of translation at the first (5′) AUG in eukaryotic mRNAs (named after Marilyn Kozak who first proposed them).
Lariat
An intermediate in pre-mRNA splicing containing the intron and 3 exon, with the branch point A residue of the intron linked via a 2‘–5’ phosphodiester bond to the nucleotide at the 5’ end of the intron. (Chapter 10)
Lysine riboswitch
An mRNA in bacteria that undergoes a change from an active (transcribed) conformation to an inactive (nontranscribed) structure when it binds lysine.
mRNA degradation control
Regulation by a cell of gene expression by selectively preserving or destroying certain mRNA molecules in the cytoplasm.
nonsense-mediated mRNA decay
Mechanism for degrading aberrant mRNAs containing in-frame internal stop codons before they can be translated into protein.
Peptidyl (P) site
The ribosome binding site that contains the tRNA to which the growing polypeptide chain is attached.
Polycistronic
Encoding several polypeptides; refers to mRNA. (Chapter 11)
Pre-mRNA
The primary transcript of a eukaryotic gene prior to processing to produce an mRNA.
Splice site
Sites at which pre-mRNA sequences are cleaved and ligated during splicing; defined by short consensus sequences. (Chapter 10)
TPP-riboswitch
An mRNA molecule whereby thiamine pyrophosphate binds to the molecule and expresses thiazole synthase to produce thiazole, a compound known for its anti-inflammatory and neuroprotective properties.
translational frameshifting
A programmed change in the reading frame during translation of an mRNA on a ribosome, occurring by any of several mechanisms.
translational repressor
A repressor that binds to an mRNA, blocking translation.
translocase
(1) An enzyme that catalyzes membrane transport. (2) An enzyme that causes a movement such as the movement of a ribosome along an mRNA.
tRNAfᴹᵉᵗ
The methionine tRNA that specifies the initiation of polypeptide chains in prokaryotes (cf. tRNAᴹᵉᵗ, tRNAᵢᴹᵉᵗ).
tRNAᵢᴹᵉᵗ
The methionine tRNA that specifies the initiation of polypeptide chains in eukaryotes (cf. tRNAfᴹᵉᵗ, tRNAᴹᵉᵗ).
tRNAᴹᵉᵗ
The methionine tRNA that responds to internal methionine codons rather than initiation codons (cf. tRNAfᴹᵉᵗ, tRNAᵢᴹᵉᵗ).
Wobble hypothesis
Hypothesis to explain how one tRNA may recognize two codons. The first two bases of the mRNA codon and anticodon pair properly, but the third base in the anticodon has some play (or wobble) that permits it to pair with more than one base.