PSL300H1 Lecture Notes - Lecture 20: Timeless (Gene), 24Hours, Arntl
Document Summary
They regulate each other v this is known as a transcription translation feedback loop (ttfl) In the morning, high levels of per/tim shut off per and tim, so per/tim levels fall. As they fall, the repression also falls: so, the genes and the mrna start working again as they are no longer repressed, and their levels start to rise. Reach a peak later in the evening: as they are transcribed, there is a peak of per and tim again in the morning. Psl300 human physiology i v this cycle oscillates: it goes up and down. Per/tim acts by blocking positive transcription factors v a gene called clock (or clk) codes a protein clk, and gene called cycle (or cyc) codes cyc. A gene called doubletime or dbt lengthens the cycle v translation is a quick process, and so we might expect per and. Psl300 human physiology i v this way, the cycle matches the 24-hour cycle.
