idk yet Flashcards
human VIP homologue in Drosophila
PDF, the receptor for which is a homologue of the the VIP receptor in the mammalian system
Why do male flies provide better information about clocks?
They don’t produce any embryos so this won’t disrupt the natural rhythms
how frequently is fly data recorded on average?
every half an hour
When do flies typically eclose?
In the morning
Typical fly cycle
Close a typically active in the 12 hour light 12 hour dark cycle in the morning and evening
What happens to flies in constant darkness?
Most of flies activity in the evening, morning peak dampens in some cases when into constant dark, but the evening peak activity is typically quite robust as it is driven by the endogenous clock
Per-short mutation
Identified because these flies appear to run the shortened phase clock, approximately 18 hours not 24 (left actogram)
Per-long mutation
Shift to the right actogram as each cycle is slightly longer than 24 hours
Per 0 mutation
Completely arrhythmic
Zeitgeber time
A.k.a. when the clock is a 12 hour light/12 hour dark cycle
Circadian time
Rhythmic cycle in constant darkness
Period gene
Clear pattern of expression, with peak appearing in early subjective night. Period mRNA peaks delayed in Per-long flies
Per
Central component of core oscillator, as mRNA shows robust rhythms in abundance, mutations in PER protein alter the speed of clock in the cells that coordinate sleep/wake cycle
Does every cell in the body clock?
No, but every part of the body does
timeless gene
Expressed in parallel to PER, with the same rhythm in mRNA, the proteins accumulate, combine with and stabilise one another, , core negative loop of the feedback mechanism
Fly eye
In each ommatidia there are 8 photoreceptors, and 7+8 project deep into the brain, all other stop in the lamina and then INs carry info to the brain
Ocelli
Also have photoreceptors at the top of the head, roughly equivalent to the mammalian pineal gland, which project into the brain
HB islet
Vestigial from larval eye, formed from the restructuring of the larval optic nerve that projects into the brain
Glia in the fly head
Also have functioning clocks, these are not important for locomotor rhythm but the locomotor-sleep-wake rhythm is disrupted if these Ns are prevented from processing neuropeptides
SLNvs
send processes to dorsal groups of neurons
LLNvs
send transhemispheric processes and processes which ramify throughout the medulla
DNs
projections are largely restricted to dorsal parts of the brain
LNds
project to SLNvs and up to DNs
SLNvs, DN1s and DN2s…
… are the only Ns that develop during embryogenesis, all other clock Ns develop later
