Molecular biology / imaging tool · BEGINNER LESSON
Reporter
A reporter in biology is a gene or molecular tool that turns a specific biological event, such as promoter activity or calcium change, into an observable signal. In these sources, reporters are often fluorescent and are used in living cells, tissues, or organisms.
What a reporter is and what it measures
A biological reporter is built to measure a chosen parameter inside a living system and convert that parameter into a visible output, usually fluorescence or enzyme activity. The measured thing may be promoter activity, a signaling event, a protein’s location, or a change in calcium concentration. Some reporters are constitutively expressed, meaning they are always on and useful for tracking cells. Others are inducible, meaning they respond to a biological signal and are used to monitor processes.
[1] Reporting from the Field: Genetically Encoded Fluorescent ... - NIHpmc.ncbi.nlm.nih.gov › articles › PMC4384825 [3] Molecular Imaging with Reporter Genes: Has Its Promise Been ...
How reporters work
A reporter system usually has two parts: a reporter gene or fluorescent protein, and a regulatory or sensing element that responds to the target event. In genetically encoded fluorescent reporters, the reporter is introduced at the DNA level, then the cell makes the reporter protein itself. The fluorescent signal can then mark where a protein is, how much of it is present, or whether a biochemical event has happened. In some designs, a molecular switch changes fluorescence resonance energy transfer, or FRET, which is the nonradiative transfer of energy between two fluorophores called donor and acceptor when they are close together.
[1] Reporting from the Field: Genetically Encoded Fluorescent ... - NIHpmc.ncbi.nlm.nih.gov › articles › PMC4384825 [3] Molecular Imaging with Reporter Genes: Has Its Promise Been ...
Why reporters are useful
Because fluorescence happens very quickly, these reporters can capture events as they unfold in real time over seconds, minutes, or hours. They can also give spatial information, because the reporter can be targeted to particular places inside a cell. This makes it possible to study dynamic signaling in live biosystems with high spatial and temporal resolution.
Limitations and tradeoffs
Reporters are not perfect measurements. The sensing element must be specific and sensitive, but the attached reporting element should not disturb the biology it is meant to track. Interactions between the reporter and native cell components can buffer cellular processes or interfere with the reporter’s function. Some fluorescent reporter systems, including GFP-based systems, can be less sensitive than enzyme-based reporters because they do not amplify the signal; they may need strong promoter activity to be detected. Reporter gene imaging also requires delivery of the reporter DNA to the target cells or tissue before imaging.
[1] Reporting from the Field: Genetically Encoded Fluorescent ... - NIHpmc.ncbi.nlm.nih.gov › articles › PMC4384825 [3] Molecular Imaging with Reporter Genes: Has Its Promise Been ...
SEE THE IDEA
How a genetic reporter turns biology into a signal
A promoter turns on, calcium changes, or proteins interact.
Detects the specific event or condition.
Produces fluorescence or another measurable output.
The change is seen or measured in living cells or tissues.
The sensing element detects the event, and the reporting element converts that detection into an observable signal.
A reporter links a chosen biological event to a measurable output.
TRY IT YOURSELF
Test your understanding
Choose an answer, then check the explanation.
PUT IT TOGETHER
Match each concept to its meaning
Drag a label onto its description, or select a label and then select a description. This also works with a keyboard.
4 pairs to match
Sources and further reading
This general lesson was generated from public source material. It explains a concept; it does not interpret a private paper or provide medical advice.