Just following on from Wolfgang's and Gerry's mails: Harry MacWilliams &
co-workers have been looking into global gene expression patterns relating
to the cell cycle. We found that pretty much all of the cell cycle related
genes, which are typically repressed by the Dicty Rb homologue, are
induced strongly during development. And while our experiments were all
done in the Ax2 background, Harry found that these genes are also
upregulated in Parikh et al's 'Dicty Express' developmental timecourses.
AX4 was the strain used in that study. So it seems that even if the cells
fail to go through cell division, the important mRNAs are still induced,
presumably driven by developmental promoter elements.

Our paper has been submitted, so we hope it should be out soon. But in the
meantime, the Dicty Express data are available (thanks to Gadi and
colleagues).

Best regards,

Gareth

> Hi Paul,
>
> To add to the debate.  A number of years ago, when we were checking
> the terminal development of ras mutants, we measured Triton X100
> resistant spore cell numbers in filter developed cells.  We routinely
> found that the parental Ax2 cells generated an increase in spores
> relative to the original number of amoebae plated and this increase
> was larger than could be accounted for by a simple division of
> binucleate cells.  Since this was not true for parental Ax3 cell
> lines (there was always a reduction in the number of spores relative
> to the original number), we checked results for NC4 and V12-M2.  Both
> wild type strains exhibited a sizeable increase, as much as 160% of
> the original.  Our conclusion was that in Ax2, NC4 and V12-M2, there
> is a sizeable amount of cell division during development.   Ax3
> develops poorly on filters, in our hands, which might account for the
> low spore numbers, or alternatively cell division does not occur
> during the development of this strain.  This may account for some of
> the reported differences in the literature.  I checked our papers and
> we never published this information, merely expressing spore
> formation in the mutant relative to spore formation in the parental
> strain (e.g. Lim et al, (2001) EMBO Journal. 20:4490-4499 and Jaffer
> et al (2001) 128:907-916).
>
> Gerry
>
>
>>Hi All,
>>
>>Is there any evidence that cells are still dividing after they have
>>entered development?  This was suggested to me at the last Dicty
>>meeting, but I haven't found anything to support that idea.
>>
>>Thanks in advance for any information you can provide.
>>
>>Best regards,
>>
>>Paul
>>
>>--
>>Paul Steimle, PhD
>>Associate Professor of Biology
>>321 McIver Street
>>University of North Carolina at Greensboro
>>Greensboro, NC 27402
>>336-334-4949
>
>
> --
> Dr. Gerry Weeks,
> Professor,
> Department of Microbiology and Immunology,
> University of British Columbia,
> 1365, Life Sciences Centre
> 2350, Health Sciences Mall,
> Vancouver, BC, V6T 1Z3,
> Canada,
> Tel  : 604-822-6649
> Fax : 604-822-6041
>