Re: Immortal Human Cells & wonderful news

Joao Pedro (
Thu, 15 Jan 1998 00:53:11 -0800


John K Clark wrote:
> Take a gene for telomerase production and a gene to turn it on and insert
> them into a sheep cell. With present techniques when you insert a gene into a
> cell it almost never finds its way to the correct place on the chromosome and
> gets expressed properly. It may take millions or billions of attempts before
> everything works correctly, but you can put trillions of cells in a test tube
> and if you also include a signaling gene for antibiotic resistance or for
> the production of a small amount of florescent dye, you can find the one
> successful cell out of billions. Then you use that cell to make a clone and
> observe if you get a cancerous sheep, an immortal sheep, or no sheep at all.
> Whatever the results of this experiment it will give us a profound lesson in
> how life works. We live in exciting times.

I'm sure that puting the telomerase gene active in adult mammals will
soon follow -- if nothing unespected happens, like I propose in the
bottom of this message. Anyway, about this great experiment, I don't
want to be the skeptic of the group but I would like to remind a couple
of things: (1) certain cells that do not divide -- post-mitotic cells
like neurons -- might also age. The proof for this is that most of the
cells of the fruit fly do not divide after adulthood and yet it shows
signs of aging; (2) non-aging species also don't have telomerase and yet
they appear not to age; (3) the behaviour of the cells "in vivo" can be
completely different; (4) even that telomerase solves all our aging
problems, how are we going to make our cells produce telomerase or at
least make its genes active?

Even so, it was a very exciting discovery that can lead us towards

CurtAdams wrote:
> I remain puzzled how telomerase could
> avert the chromosomal traslocations, fissions, and fusions characteristic
> of senescing cells and wonder if the human telomerase has regulatory
> functions as well as enzymatic ones.

Here's a question for you, if our cells have the genes that code for
telomerase, why isn't it active in all cells? Could it be that
telomerase has other functions? Could it be that the genes of telomerase
code other proteins that must be inibited after cellular
differentiation? Could it be that telomerase is harmful in some tissues?

         Hasta la vista...

"Life's too short to cry, long enough to try." - Kai Hansen Reason's Triumph at: