Regulation pt. 2 Flashcards
what are regulatory RNAs
they affect gene expression post-transcriptionally (interacting with proteins, bind to complementary sequences of target transcripts)
what are the three types of regulatory RNAs
riboswitches, cis-antisense RNA (asRNA), and small RNA (sRNA)
where are riboswitches usually located / what does a riboswitch do
5’ UTR / can control transcription or translation
what does the ligand binding of the riboswitch do to regulate transcription
the ligand changes the conformation of the 5’ UTR which forms the loop and terminates transcription
what does ligand binding of the riboswtich do to regulate translation / do riboswitched that control translation affect transcription
moves the ribosome binding site to be a double strand which cannot be recognized / no they do not
what is an asRNA
700-3,000 nt that is transcribed from the non template of DNA where it can only regulate the gene/operon it was transcribed from
how is asRNA usually involved in regualtion / how does it do it
usually just one part of highly regulated proteins / physically blocks the RNAP as it is going the opposite direction - premature termination
what are sRNAs / what can they do
small RNAs that mostly function by binding the complementary sequence within mRNA / can either inhibit or activate translation
what are the benefits of sRNAs
they are economical and rapid (no translation required) acts on any mRNA already made - regulates very quickly
what is regulates feric uptake / what is it based on
a sRNA / based on iron availability - presence of lots of iron the Fur repressor binds the iron to repress the gene - low iron fur falls off
what is environmental sensing / what is the process of recognizing a stimulus
the cell senses things from the environment such as starvation, heat, light, etc. / stimulus, sensor (in membrane), transducer (second messenger), response regulator (change specific gene expression in response to transduction), feedback mechanism (turns off mechanism)
what are second messengers not
NOT biosynthetic precursors, NOT required for survival
what do second messengers do
transmit messages within and between cells often controlling expression of multiple operons
what is ppGpp / what does it do
made during the stringent response when bacteria experience amino acid starvation / changes RNAP affinity for certain promoters
what are alternative sigma factors / what are sigma factors required for
make large readjustments based on the environment (response to multiple environmental stressors) / required for transcription initiation, not elongation
