[bksvol-discuss] Re: OT: UCLA identifies enzyme linked to childhood blindness
- From: "Paula and James Muysenberg" <outofsightlife@xxxxxxxxxxx>
- To: <bksvol-discuss@xxxxxxxxxxxxx>
- Date: Fri, 12 Aug 2005 14:32:08 -0500
Hi, Cindy,
I couldn't follow all this, but it is fascinating. I recently read and
validated a book Sarah submitted, called Darwin's Black Box, by Michael
Behe. Reading all that technical description about enzymes and the visual
process seemed like another page out of Behe's book. It's funny how, since I
read the book, similar material seems to keep popping up.
Thanks for forwarding this article.
Paula Muysenberg
----- Original Message -----
From: "Cindy" <popularplace@xxxxxxxxx>
To: <bksvol-discuss@xxxxxxxxxxxxx>
Sent: Friday, August 12, 2005 1:27 AM
Subject: [bksvol-discuss] OT: UCLA identifies enzyme linked to childhood
blindness
> I heard an quick item on the car radio, and when I
> came home I looked it up. This may be of some interest
> to some of you.
>
> Cindy
>
> UCLA researchers identify key enzyme linked to
> childhood blindness
>
> Findings could lead to gene therapy cure
> In findings that could lead to curing some forms of
> congenital blindness through gene therapy, researchers
> at UCLA have discovered that RPE65, a gene missing in
> infants born with the blinding disease Leber
> congenital amaurosis, is also a key enzyme in the
> visual cycle. The identity of this enzyme has long
> been a mystery to scientists.
>
> The study, "Rpe65 is the Retinoid Isomerase in Bovine
> Retinal Pigment Epithelium," is published in the Aug.
> 12 issue of Cell magazine.
>
> "We were amazed when we discovered the function for
> Rpe65 -- and that Rpe65 is the retinoid isomerase. It
> is a protein that all of us had known about for
> years," said Dr. Gabriel Travis, professor of
> ophthalmology and biological chemistry at UCLA's Jules
> Stein Eye Institute and one of the researchers. "It's
> like searching the world for a treasure, then
> discovering it in your own back yard."
>
> Leber congenital amaurosis is an inherited disease
> that is believed to cause up to 20 percent of all
> cases of childhood blindness. It is caused by
> mutations in several different genes including RPE65.
> An important characteristic of this disease is that
> the light sensitive rod and cone cells remain intact
> in the retinas of Leber patients for a long time.
>
> "This suggests that replacement of RPE65 by gene
> therapy should correct the blindness in these
> children, as was observed in mice and dogs with RPE65
> mutations," Travis said. "This is a major breakthrough
> in understanding the visual cycle. It has
> ramifications for several inherited blinding diseases
> caused by mutations in visual cycle genes."
>
> The newly identified isomerase enzyme plays a crucial
> role in the regeneration of rhodopsin visual pigment
> in the retina after light exposure. Rhodopsin contains
> a light absorbing molecule called 11 cis
> retinaldehyde, related to vitamin A, which is
> converted upon light absorption to all trans
> retinaldehyde in a process called photo bleaching.
> This conversion is the first step in visual
> perception.
>
> Photo bleaching leaves the rhodopsin insensitive to
> light until the all trans retinaldehyde is converted,
> or "isomerized," back into 11 cis retinaldehyde, which
> completes the visual cycle. Scientists have for two
> decades been attempting to identify the retinoid
> isomerase enzyme that catalyzes this regeneration of
> 11 cis retinaldehyde. Scientists have also been
> stumped by the function of the Rpe65 protein
>
> Working with Travis at the Jules Stein Eye Institute,
> Dr. Minghao Jin, visiting assistant researcher in
> ophthalmology, performed an expression screen in
> cultured human cells, looking for a gene that caused
> these cells to convert vitamin A into 11 cis retinol.
>
> The researchers are now studying the effects on
> retinoid isomerase activity of specific disease
> causing mutations in the RPE65 gene, which should
> provide more data on the cause of Leber congenital
> amaurosis and on how the Rpe65 protein works. The
> researchers are also examining the function of other
> proteins that work closely with Rpe65. Mutations in
> the genes for these interacting proteins are linked to
> other forms of human blindness.
>
> "These results settle the long standing mystery about
> the identity of the retinoid isomerase," Travis said.
> "Scientists have been searching for this enzyme for
> almost 20 years. Our results also explain why finding
> this enzyme has been so difficult, until now."
>
> Other researchers on this project besides Travis and
> Jin are Hui Sun, assistant professor of physiology at
> UCLA, and Songhua Li and Walid Moghrabi, staff
> research associates at the Jules Stein Eye Institute.
>
> ###
>
> The National Eye Institute, the Foundation for
> Fighting Blindness, and Research to Prevent Blindness
> funded the study.
>
>
>
>
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