responses to "leaf-specific

Detlef Weigel detlef_weigel at QM.SALK.EDU
Thu Nov 3 12:31:19 EST 1994


Thanks to every body who responded to my question regarding leaf-specific
promoters.  Besides CAB and RBCS,  GAPA, GAPB and ST-LS1 seem to be very
specific to all photosynthetic tissues.  Plus there is a Brassica gene that
might be particularly specific for young leaves, but not shoot meristems. The
responses are listed below.

Detlef Weigel.

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Cab promoters are expressed strongly in young leaves, but
there is always a small amount of expression in the hypocotyl,
none at all in the roots.

I think you will find the CAB promoter expressing in leaf
primordia, at least it looks like that when we do close-up optics
with luc assays. Another route maybe to try a synthetic promoter
- Check out Eric Lam's papers (Plant cell 1, 1147 1989; Plant J.
3, 509 1993) for the pattern conferred by as2 elements and the
like. However, note that if people have hooked these up to the
-90 35S promoter, then you will probably get meristematic
background from that construct.

Steve Kay

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I don't known of anything that's absolutely leaf specific,
but expression of a number of photoregulated genes such as 
RBCS, CAB, and GAPA or GAPB of Arabidopsis is almost entirely
in leaves (some other green tissues may show low levels of the
mRNAs of these genes).  My own personal experience with these genes,
as well as published results, says that these are expressed
well in young leaf tissues and cotyledons.  Of the lot, CAB
may have the strongest promoters, followed by RBCS and then
the GAPA and GAPB genes. Hope this helps.  Cheers!

Terry Conley

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Jorg Stockhaus has several leaf specific promoters, even palisade specific
ones. One of them is called ST-LS1 or L700 EMBO J. 8, 2445 (1989). He is in
Duesseldorf with Peter Westhoff now
Wolf

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 *        Wolf B. Frommer                                   *
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Try the small subunit promoter of Rubisco

Charlie Spillane,
Genetics Dept.
Trinity College,
Dublin 2.
IRELAND.

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We have isolated several members of a gene family and one of the members 
appears to be young leaf specific (based on polyA Northerns). 

On the Northern blot we see a strong signal for 1-3 mm leaves, but no 
signal for 10-30 mm or >150 mm leaves in Brassica napus.
We also see a lower signal in the shoot apex lane but believe this to 
represent the young leaf tissue present in the shoot apex dissected region.
We are presently doing in situs to demonstrate that expression is not in 
the shoot apical meristem but only in very young leaves.

The clone we have is a cDNA. We have not characterized or subcloned the 
genomic clones we have isolated from a library screen.

Since the information on the cDNA has been accepted for publication but 
not yet appeared if you are interested in the gene name and clone I will 
have to clear it with my supervisor first.

I presume you want to use the promoter to express something of interest 
to you and that you are not directly interested in what regulates young 
leaf specific expression. The latter is something we are pursuing with 
respect to our clone.



_______________________________________________________________________
Steven Szarka                              Dept. of Biological Sciences      
Email: sjszarka at acs.ucalgary.ca            University of Calgary             
FAX: (403) 289-9311                        2500 University Drive NW          
                                           Calgary, AB, Canada T2N 1N4      
_______________________________________________________________________





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