Cry double knockouts

Stanewsky There is one aspect of the Cry double knockout behaviour that has always puzzled me. It never looked to me that it was just masking, because they seem to anticipate the LD transition. This would fit perfectly with your assumption that it is an hour-glass mechanism. 

Van Gelder A clarification. The restored transplant is a wild-t3rpe SCN into a cry double knockout. Is the Crj double-mutant SCN-lesioned ... 

Hastings In the SCN of the Cry double-knockout mice, the PER2 protein is destabilized. There is no PER2 protein, even though there is mRNA. In Steve s knockouts, if you knockout some of the PERs then you destabilize the CRYs. There is a reciprocal co-stabihzation taking place in the SCN. 

Takahashi If you have a mouse that is clockless it is much more susceptible to disturbances. In clock mutants that are arrhythmic, if you are not careful the noise in the animal facility wiU actually drive a diurnal day-active activity pattern. We see this in Cry double knockouts too. They are arrhythmic, so they are highly susceptible to being disturbed. This leads to this diurnal activity pattern. 

Sassone-Corsi That s a good question, and we haven t done this. I would expect the effects to be from the SCN, but we need to do this experiment. I would love to see a SCN transplant in a Clock mutant mouse. But if what Bert van der Horst said in his paper (Bonnefont et al 2003, this volume) is true, that peripheral clocks are not working in Cry double knockouts where a normal SCN is introduced, this teUs me that all peripheral oscillators are not crucial for motor rhythmic activity. Could the SCN be the only thing responsible for aU the rhythmic activity I am not sure how much peripheral tissues are working in those Cry double knockouts. 

Sassom-Corsi I m very excited by the experiment that involved transplanting the normal SCN into the double Cry knockout mutants (Sujino et al 2003). This could tell us a lot about the relationship between the SCN masking and the entrainment of the other tissues. 

Sassone-Corsi I agree. What we don t know is how much the liver, for example, is affected in the double Cry knockout. 

Roshash In the double Cry knockouts, what are the levels of the clock proteins such as PER, relative to a wild-type oscillatory cycle ... 

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