Alarmone
Encyclopedia
Alarmone is an intracellular
signal molecule that is produced due to harsh environmental factor
s. They regulate the gene
expression at transcription level. Alarmones are produced in high concentrations when harsh environmental factors occur in bacteria
and plants, such as lack of amino acid
s to produce protein
s. Stringent factors take uncharged tRNA
and converts it to an alarmone. GDP converted is then converted to 5´-diphosphate 3´-diphosphate guanosine (ppGpp), the archetypical alarmone. ppGpp will bind to RNA polymerase β and β´subunits, changing promoter preference. It will decrease rRNA and other genes transcription but will increase transcription of genes involved in aminoacid biosynthesis and metabolisms involved in famine .
Intracellular
Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...
signal molecule that is produced due to harsh environmental factor
Environmental factor
Environmental factor or ecological factor or ecofactor is any factor, abiotic or biotic, that influences living organisms.- Environmental factors inducing diseases :...
s. They regulate the gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
expression at transcription level. Alarmones are produced in high concentrations when harsh environmental factors occur in bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
and plants, such as lack of amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s to produce protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s. Stringent factors take uncharged tRNA
Transfer RNA
Transfer RNA is an adaptor molecule composed of RNA, typically 73 to 93 nucleotides in length, that is used in biology to bridge the three-letter genetic code in messenger RNA with the twenty-letter code of amino acids in proteins. The role of tRNA as an adaptor is best understood by...
and converts it to an alarmone. GDP converted is then converted to 5´-diphosphate 3´-diphosphate guanosine (ppGpp), the archetypical alarmone. ppGpp will bind to RNA polymerase β and β´subunits, changing promoter preference. It will decrease rRNA and other genes transcription but will increase transcription of genes involved in aminoacid biosynthesis and metabolisms involved in famine .