Regulation of protein concentration: expressed destroyed or created

1. DNA topology:

supercoiling and looping of DNA can make genes more or less accessible to transcription machinery.

2. Promoter Recognition:

Different sigma factors (σ⁷⁰, σ^S, σ^H) guide RNA polymerase to specific promoter sequences

3. Transcriptional Repression

Repressor proteins bind to operator regions, blocking RNA polymerase from initiating transcription.

4. Transcriptional Activation

Activator proteins (inactive until bound by a ligand) help RNA polymerase bind the promoter.

5. Transcriptional Enhancement

DNA looping brings enhancer elements closer to the promoter via DNA-bending proteins and activators.

6. Transcription Termination

Specific sequences in the DNA cause premature termination of transcription.

7. Regulatory sRNA (Small RNA):

Small RNAs bind to mRNAs or proteins to block or enhance translation

8. Messenger Stability:

Stability of the mRNA affects how long it is available for translation

9. Translational Control:

Regulation occurs after mRNA is made, often through proteins or RNAs that block translation initiation.

10. Proteolysis

Unwanted or damaged proteins are broken down by proteases.

11. Localization of Protein:

Proper targeting of proteins to specific cellular locations (e.g., membrane, cytoplasm) is crucial.