Regulation of Gene Expression Lecture 16 Regulation of Gene Expression

Gene expression: the process by which a gene’s DNA sequence is converted into a gene product – protein (mRNA), tRNA, or rRNA Each step in the process of gene expression can be regulated

DNA is packed into chromatin

Step1: Modifying the chromatin structure: histone acetylation or methylation

Step 2: Regulation of Transcription

Promoter/Enhancer function depends on available transcription factors: different cells have different transcription factors available

Step 3: Post-transcriptional Regulation

Step 4: Regulating mRNA stability and Step 5: Regulating Initiation of Translation

Step 6: Regulating Protein Stability

Genetic changes that make things go awry….. proto-oncogene: a normal gene that can become an oncogene oncogene: a modified gene that encodes for a protein that can increase the chance that a normal cell can become a tumor cell or convert a tumor cell to a malignant cell

ras: GTP-binding protein -part of the MAPK pathway (signal transduction) -this pathway induces cell division p53: DNA binding protein -holds a cell at the G1/S or G2/M boundary -induces DNA repair machinery