Which gene controls transcription of chain A and chain B required for humulin synthesis in E. coli?

Options

A. `beta`- Lactamase
B. `beta`-Galactosidase
C. Polygalacturonase
D. Chitinase

Answer

To answer the question about which gene controls the transcription of chain A and chain B required for Humulin synthesis in E. coli, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Humulin**:
- Humulin is the synthetic form of human insulin, which consists of two peptide chains: chain A and chain B.

2. **Cloning of Insulin Chains**:
- The genes coding for chain A and chain B of insulin are cloned separately. This is a crucial step in the biotechnology process to produce Humulin.

3. **Use of Plasmid**:
- The cloned genes for chain A and chain B are inserted into a plasmid, specifically the plasmid PBR322. This plasmid serves as a vector to introduce the insulin genes into E. coli.

4. **Fusion with E. coli Gene**:
- The cloned synthetic genes for the insulin chains are fused with the gene for E. coli beta-galactosidase. This fusion is essential for efficient transcription and translation of the insulin chains.

5. **Role of Beta-Galactosidase**:
- The beta-galactosidase gene not only aids in the transcription of the insulin chains but also helps in the translation process, ensuring that a stable precursor protein is formed.

6. **Conclusion**:
- Therefore, the gene that controls the transcription of chain A and chain B required for Humulin synthesis in E. coli is the **beta-galactosidase gene**.

### Final Answer:
The gene that controls the transcription of chain A and chain B required for Humulin synthesis in E. coli is the **beta-galactosidase gene**.

---