Selenoproteins are not described well among species. For this reason, we decided to perform this project in order to identify selenoproteins in L. laticaudata genome. To do this, we compared it with a model organism: Homo sapiens, since the proteins in these species are habitually well-conserved.

In this study, we could predict a total of 26 selenoproteins, 8 cysteine homologues of existing selenoproteins and 4 machinery proteins that synthesized the selenoproteins in Homo sapiens.

The following tables below illustrate the results obtained for L. laticaudata:

It is important to highlight that only one protein duplication has been taken place (SBP2). Moreover, 5 proteins were missing in L. laticaudata genome: SelR2, SelV, SelU3, GPx5, GPx6. There were many selenoproteins that we could not predict because they did not contain either a Sec residue or a SECIS element (GPx3, SelH, SelK, SelM, SelS, TR1, TR2, TR3). And, in the same way, we could not predict a cysteine-containing homolog due to the gain of a Sec residue and a SECIS element (MsrA). The rest of the proteins were homologous to those described in the human genome. So, we have found 33 proteins, 15 of which were Sec-containing selenoproteins (GPx1, GPx2, GPx4, DI1, DI2, DI3, Sel15, SelI, SelN, SelO, SelP, SelR1, SelT, SelU1 and SelW1), 5 were Cys-containing homologs (GPx7, GPx8, SelR3, SelU2, SelW2) and 4 machinery proteins (eEFSec, SPS1, SPS2, SBP2). Some contained a Sec residue in their sequences although no SECIS elements in 3’UTR region could be found. These might be selenoproteins because Seblastian compares our proteins with another species and some errors may have taken place.

During this study, the main limitation observed was the fragmentation that presents the L. laticaudata genome. So, in many cases we could not predict correctly the proteins due to the absence of some parts. As a consequence, we found several proteins divided in differents scaffolds, thus, there are insertions and deletions that caused frameshifts.