Model animals, resembling mice and fruit flies, have provided scientists with powerful insights into how cellular biology works. Nonetheless, model animals are really only a guide, and it might probably be dangerous to generalize findings across animals from studying a number of model organisms.

Cysteine is a crucial amino acid utilized in multiple biological processes, including metabolism and protein synthesis. In animals, cysteine biosynthesis was regarded as created exclusively via the transsulfuration pathway, with the cystathionine β-synthase (CBS) enzyme as a key player. Nonetheless, previous research indicated that the CBS gene had been lost in corals of the genus Acropora. The suggestion was that these corals couldn’t produce cysteine themselves and needed to depend on symbiotic relationships with algae to receive it.

“We weren’t looking for possible cysteine biosynthesis in Acropora,” says postdoc Octavio Salazar, who worked on a Center Partnership Fund project with Principal Investigator Manuel Aranda from KAUST and colleagues from the Australian Institute of Marine Science. “We were generating a high-quality genome of the coral Acropora loripes as a precious genomic resource for future research.”

With the high-resolution genome complete, the team decided to see in the event that they could confirm that the CBS gene was indeed missing. Salazar could find no sign of the gene on the locus where it was meant to be, but he and his colleagues weren’t convinced that the coral had no other way of synthesizing cysteine.

“I began searching the genome for genes encoding for enzymes that looked much like those in other known cysteine biosynthesis pathways, resembling those present in fungi and bacteria,” says Salazar. “I used to be quite surprised to seek out two enzymes within the coral with similarities to a recently identified alternative cysteine biosynthesis pathway in fungi.”

To substantiate that the enzymes encoded by these coral genes could synthesize cysteine in vivo, the researchers used yeast mutants with no cysteine biosynthesis capability and gave them the corresponding Acropora genes. The mutants began producing cysteine.

Further, the KAUST team found that each genes were present within the genomes of all animal phyla aside from vertebrates, arthropods and nematodes -; the precise three groups that probably the most common animal model organisms come from.

“This study proves the worth of keeping an open mind in the case of studying living creatures,” says Aranda. “Sometimes knowledge can put you in a box; in case you analyze data using only what you’re thinking that you realize, you might well miss something. Our Acropora genome will probably be hugely precious for future studies and who knows, it could reveal other unexpected details along the best way.”

Source:

King Abdullah University of Science & Technology (KAUST)

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