Sea Urchin Genome Suprisingly Similar To Man And May Hold Key To Cures

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Sea Urchin Genome Suprisingly Similar To Man And May Hold Key To

Cures

http://www.medicalnewstoday.com/medicalnews.php?newsid=58507

Sea urchins are small and spiny, they have no eyes and they eat kelp

and algae. Still, the sea creature's genome is remarkably similar to

humans' and may hold the key to preventing and curing several human

diseases, according to a University of Central Florida researcher

and several colleagues.

UCF Professor Cristina Calestani was part of the Sea Urchin Genome

Sequencing Group, which recently completed sequencing of the sea

urchin genome and published its findings in the November issue of

Science. The National Institutes of Health funded most of the nine-

month project.

The genome of the purple sea urchin is composed by 814

million " letters " coding for 23,300 genes.

Sea urchins are echinoderms, marine animals that originated more

than 540 million years ago. The reason for the great interest in

sequencing the sea urchin genome is because it shares a common

ancestor with humans. Sea urchins are closer to human and

vertebrates from an evolutionary perspective than other more widely

studied animal models, such as fruit fly or worms. The purple sea

urchin, in fact, has 7,000 genes in common with humans, including

genes associated with Parkinson's, Alzheimer's and Huntington's

diseases and muscular dystrophy.

" Another surprise is that this spiny creature with no eyes, nose or

hears has genes involved in vision, hearing and smell in humans, "

Calestani said. " The comparison of human genes with their

corresponding ancestral sea urchin genes may give important insight

on their function in humans, in the same way the study of history

helps understanding the reality of our modern world. "

The genome sequencing project was led by a Sodergren and

Weinstock at the Baylor College of Medicine-Human Genome Sequencing

Center in Houston, along with Dr. Gibbs, director of the

Baylor center, and Drs. son and Cameron at the

California Institute of Technology.

Of particular interest to Calestani is the way the sea urchin's

immune system works. The human immune system has two components:

innate immunity, with which we are born, and acquired immunity,

which is the ability to produce antibodies in response to an

infection. Sea urchins only have innate immunity, and it is greatly

expanded with 10 to 20 times as many genes as in human.

" Considering that sea urchins have a long life span -- some can live

up to 100 years -- their immune system must be powerful, " Calestani

said. " Sea urchins could very well provide a new set of antibiotic

and antiviral compounds to fight various infectious diseases. "

The sea urchin has been used for many years as a research model to

study embryonic development.

Cell development is very complicated. In order to properly regulate

just one gene expression of a single-cell layered gut of the sea

urchin larva, at least 14 proteins binding the DNA at 50 sites are

needed, Calestani said.

" Multiply that hundreds of times and you begin to understand the

level of complexity involved in human development, " she added.

Using a " simple " creature like the sea urchin embryo to uncover the

molecular basis underlying development offers several experimental

advantages compared to the use of mice. Raising sea urchin embryos

is easy and inexpensive. One female can provide up to 20 millions

eggs. The embryos develop in just three days and are transparent.

Also, single cells can be easily observed live in the embryos.

" If we know how these biological processes work, then we can begin

to figure out how to intercede to repair and to heal, " Calestani

said. " It holds a lot of promise. "

Calestani is continuing her work with sea urchins at UCF in Orlando

by examining the development of pigment cells found in the marine

creatures. Those cells also might provide some insight into human

immunity to diseases.

Calestani, who teaches genetics at UCF, worked with son at

Caltech before arriving at UCF.