Once upon a time in the DNA Repair City, lived a curious young scientist named Meera. This city was home to a long and precious scroll called DNA, which carried all the instructions needed to run the city. But this scroll was very delicate and often got little tears, smudges, or missing letters. Luckily, five superheroes known as Polymerase Protectors (Pol I to V) guarded the DNA scroll.
🧪 Chapter 1: Pol I – The Cleanup Master (Gene: polA)
One day, Meera saw a superhero with a magnifying glass and scissors, carefully removing little sticky notes (RNA primers) from the scroll and replacing them with proper DNA. This was Pol I, the Cleanup Master.
“I’m not fast,” Pol I told Meera, “but I’m good at cleaning up mistakes. I can also fix small nicks and fill gaps. See? I even proofread!”
Pol I had three tools:
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A pen to write DNA (5'→3' polymerase),
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An eraser to remove wrong letters from the end (3'→5' proofreading),
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And scissors to snip out damaged or RNA parts from the start (5'→3' exonuclease).
Meera noted down: Gene: polA — For primer removal and DNA repair.
🔬 Chapter 2: Pol II – The Quiet Rescuer (Gene: polB)
Next, Meera met a calm and steady hero, Pol II, hiding in the background.
“I come when DNA is hurt or stuck,” said Pol II. “When the main worker gets stuck, I step in and gently fix things.”
Pol II specialized in restart repair and careful copying after stress. He wasn't the main worker, but always ready in emergencies.
Meera’s notes: Gene: polB — For DNA repair and stress recovery.
⚙️ Chapter 3: Pol III – The Speed Star (Gene: dnaE and friends)
Suddenly, a blur zoomed by! Meera saw a high-speed hero with multiple arms — Pol III, the Main Builder of the city.
“I’m the fastest! I build most of the DNA scroll during replication,” said Pol III proudly. “But I don’t work alone. I have a whole team!”
Pol III had:
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A pen hand (alpha, dnaE) to write,
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A proofreading hand (epsilon, dnaQ) to catch errors,
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A steadying hand (theta, holE) for support,
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And a sliding clamp that helped him stay attached like Velcro!
Meera gasped: “You’re the main construction crew!”
Gene: dnaE, dnaQ, holE — Main replicative polymerase.
🧫 Chapter 4: Pol IV – The Risk-Taker (Gene: dinB)
Next, Meera heard a loud crash. A daring, slightly clumsy superhero was jumping over broken parts of DNA!
“I’m Pol IV,” he said. “Sometimes when DNA has damage, someone’s gotta keep going. I take risks and fill in the gap — even if it’s not perfect.”
He was part of the SOS response — emergency services when the city is under attack from UV rays or chemicals. He could bypass lesions, but often introduced typos.
Meera’s notes: Gene: dinB — For translesion synthesis (damage tolerance).
⚠️ Chapter 5: Pol V – The Emergency Fighter (Genes: umuC and umuD)
In the deepest part of the city, Meera met the final hero — a serious and slightly dangerous one. It was Pol V, created only in extreme emergencies.
“When DNA is severely damaged and no one else can help,” said Pol V, “I step in. I’m not accurate, but I’ll make sure the scroll is complete, no matter what.”
Pol V worked as a team: UmuD’2C — a combination of two UmuD and one UmuC. Together, they acted like a desperate repair crew under fire.
Meera’s notes: Genes: umuC and umuD — for SOS-induced error-prone DNA synthesis.
🧠Meera’s Final Summary:
| Polymerase | Gene(s) | Role in DNA City |
|---|---|---|
| Pol I | polA | Removes RNA primers, fills gaps, repairs |
| Pol II | polB | Helps in DNA repair and restart |
| Pol III | dnaE, dnaQ, holE | Main enzyme for DNA replication |
| Pol IV | dinB | Damage bypass during stress (error-prone) |
| Pol V | umuC, umuD | Emergency damage bypass (error-prone, SOS) |
And with that, Meera closed her notebook, grateful to have met the five polymerase protectors who kept the DNA City safe and functioning. She now understood that each had a special job, and together they made sure life continued smoothly — even when things went wrong.
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