B/12 Flashcards
Types of epigenetic alterations that can have a role in cancer development (2)
- DNA methylation
- Micro-RNA expression
Which enzyme methylates DNA?
DNA methyltransferase
What happens with hypermethylation of a promoter?
No more transcription of a certain exon
3 examples of genes that are frequently hypermethylated in cancers
- APC
- VHL
- CDKN2B
What cancer does hypermethylation of APC cause?
colorectal carcinoma
What cancer does hypermethylation of VHL cause?
renal cell carcinoma
What cancer does hypermethylation of CDKN2B cause?
leukemia
What is the role of micro RNA?
they are negative regulatory fragments of coding sequence
How long are miRNA?
22 nucleotide long
What cuts pre-miRNA in the cytoplasm?
Dicer
What happens to the cut pre-miRNA?
it is incorporated into the RISC complex
What does the RISC complex do? (2)
- repress mRNA translation
- cleaves mRNA
Example of oncogene miRNA and its neoplasm
miR-21 : glioblastoma
Example of tumor suppressor miRNA and its neoplasm
miR-15a : CLL