Comparative sequence analysis of the complete set of 40S ribosomal proteins in the Senegalese sole (Solea senegalensis Kaup) and Atlantic halibut (Hippoglossus hippoglossus L.) (Teleostei: Pleuronectiformes): phylogeny and tissue- and development-specific expression.
BACKGROUND
Ribosomal proteins (RPs) are key components of ribosomes, the cellular organelle responsible for protein biosynthesis in cells. Their levels can vary as a function of organism growth and development; however, some RPs have been associated with other cellular processes or extraribosomal functions. Their high representation in cDNA libraries has resulted in the increase of RP sequences available from different organisms and their proposal as appropriate molecular markers for phylogenetic analysis.


RESULTS
The development of large-scale genomics of Senegalese sole (Solea senegalensis) and Atlantic halibut (Hippoglossus hippoglossus), two commercially important flatfish species, has made possible the identification and systematic analysis of the complete set of RP sequences for the small (40S) ribosome subunit. Amino acid sequence comparisons showed a high similarity both between these two flatfish species and with respect to other fish and human. EST analysis revealed the existence of two and four RPS27 genes in Senegalese sole and Atlantic halibut, respectively. Phylogenetic analysis clustered RPS27 in two separate clades with their fish and mammalian counterparts. Steady-state transcript levels for eight RPs (RPS2, RPS3a, RPS15, RPS27-1, RPS27-2, RPS27a, RPS28, and RPS29) in sole were quantitated during larval development and in tissues, using a real-time PCR approach. All eight RPs exhibited different expression patterns in tissues with the lowest levels in brain. On the contrary, RP transcripts increased co-ordinately after first larval feeding reducing progressively during the metamorphic process.


CONCLUSIONS
The genomic resources and knowledge developed in this survey will provide new insights into the evolution of Pleuronectiformes. Expression data will contribute to a better understanding of RP functions in fish, especially the mechanisms that govern growth and development in larvae, with implications in aquaculture.
Manchado
Manuel
M
IFAPA Centro El Toruño, Junta de Andalucía Camino Tiro de pichón s/n, El Puerto de Santa María, Cádiz, Spain. manuel.manchado.ext@juntadeandalucia.es
Infante
Carlos
C
Asensio
Esther
E
Cañavate
Jose Pedro
JP
Douglas
Susan E
SE
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D003199:Computer Systems; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D020224:Expressed Sequence Tags; D005412:Flatfishes / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D005432:Flounder / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D020440:Gene Duplication; D018507:Gene Expression Regulation, Developmental; D015723:Gene Library; D016678:Genome; D007814:Larva; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D009928:Organ Specificity; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D021122:Protein Subunits; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012269:Ribosomal Proteins / Q000096:biosynthesis / Q000235:genetics*; D016415:Sequence Alignment; D017385:Sequence Homology; D014158:Transcription, Genetic
D018076:DNA, Complementary; D009419:Nerve Tissue Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D012269:Ribosomal Proteins