Today''s Page Hits: 15
This page validates as XHTML 1.0, and will look much better in a browser that supports web standards, but it is accessible to any browser or Internet device. It was created using techniques detailed at glish.com/css/.
Wednesday September 13, 2006 Questions for Wildwater:
1) What exactly are "lox" recombination sites?
2) Their interpretation was that SCR has opposing effects in relation to RBR function and activity--what might this mechanism look like?
3) Where is the proximal meristem? What makes proximal meristematic cells different from other meristems in the root? Does the lack of effect on proximal meristems by rBRr imply that these cells are maintained by a separate pathway?
If they used Dex to try and restore root growth in
scr-4 rRBr plants and it did not work, would this be
because RBR gene is downstream of SCR?
Why did they use scr-4?
I am a little confused. Was root growth reduced by RBR
overexpression (1343) and by the scr-4 rRBr mutant as
well?
1. What exactly are "lox" recombination sites?
lox are abou 35 bp sites recognized by Cre. Lox sites flanked RBR and a heat shock inducible Cre enzyme was used to remove RBR and simultaneously restore GFP expression.
2. Good question, Mark. I'm still thinking....
3. Where is the proximal meristem?
RAM proper, nearer to root shoot junction.
What makes proximal meristematic cells different from other meristems in the root?
Auxin?
Does the lack of effect on proximal meristems by rBRr imply that these cells are maintained by a separate pathway?
Or a redundant gene active in RAM but not the distal, root cap meristem.
Posted by Niki on September 13, 2006 at 10:12 PM EDT #
If they used Dex to try and restore root growth in
scr-4 rRBr plants and it did not work, would this be
because RBR gene is downstream of SCR?
Dex induction was the last paper. They run together... this one used used heat shock induction instead of dex induction.
Why did they use scr-4?
They presume RBR is downstream of SCR, which is downstream of SHR.
I am a little confused. Was root growth reduced by RBR overexpression (1343) and by the scr-4 rRBr mutant as well?
Yes. They explain this by saying that increased cell division in the double mutant doesn't lead to increased root growth because the cells don't expand.
Posted by Niki on September 13, 2006 at 10:38 PM EDT #
2) Their interpretation was that SCR has opposing effects in relation to RBR function and activity--what might this mechanism look like?
I think I have it. Western blot shows reduced RBR in scr-4 mutant compared to wt. Therefore SCR increases RBR, which is needed for cell cycle. But SCR involved in pattern formation, not cell cycle.
Do you believe RBR accumulation is down in scr-4 (Fig. 1K)? Remember SCR expressed in a single layer of cells while RBR expressed throughout meristem.
Posted by Niki on September 13, 2006 at 10:46 PM EDT #
I believe that we stated that IAA plays a role in differentiation of the RAM. Secondly the root growth was reduced by overexpression of RBR presumably since the stem cells would have been lost to differentiation. I am still not clear how two layers of stem cells could form though.
Posted by Cat on September 14, 2006 at 09:13 AM EDT #