The evolutionary relationship of the transcriptionally-active fabp11a (intron-less) and fabp11b genes of medaka with fabp11 genes of other teleost fishes
- Authors
- Parmar, M.B., Venkatachalam, A.B., and Wright, J.M.
- ID
- ZDB-PUB-120424-18
- Date
- 2012
- Source
- The FEBS journal 279(13): 2310-2321 (Journal)
- Registered Authors
- Wright, Jonathan M.
- Keywords
- intron-less gene, fabp11, whole-genome duplication, teleost, medaka
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Base Sequence
- DNA, Complementary/genetics
- Evolution, Molecular*
- Fatty Acid-Binding Proteins/genetics*
- Fishes/genetics*
- Genomics
- Introns/genetics
- Molecular Sequence Data
- Organ Specificity
- Oryzias/genetics*
- Phylogeny
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Synteny*
- Transcription, Genetic*
- PubMed
- 22520026 Full text @ FEBS J.
In this report, we describe the structure of fatty acid-binding protein 11a (fabp11a) and fabp11b genes in medaka and their evolutionary relationship to fabp11 genes from other teleost fishes. Initial studies indicated that the medaka fabp11a gene is intron-less, while the fabp11b gene consists of four exons separated by three introns, a genomic organisation characteristic of most members of the intracellular lipid-binding protein family. Based on genomic sequence, we conclude that the intron-less fabp11a gene most likely arose as a result of the reverse transcription of its mRNA transcript into cDNA followed by its integration into chromosomal DNA. The ancestral intron-containing fabp11a gene was presumably lost from the medaka genome. The duplicated fabp11 genes extant in medaka code for polypeptides of 134 amino acids, which share highest sequence identity and similarity, and cluster in a distinct phylogenetic clade with their orthologs in other teleost fishes. The fabp11a and fabp11b genes in medaka are, therefore, orthologs of the fabp11a and fabp11b genes of teleost fishes, respectively. No conserved gene synteny was found between medaka fabp11a and fabp11a genes from other teleost fishes supporting our contention of how this intron-less gene arose. Conserved gene synteny was, however, evident between medaka fabp11b and fabp11b from other teleost fishes. The tissue-specific distribution of transcripts for medaka and zebrafish fabp11a and fabp11b genes revealed the acquisition of new function(s) in different tissues by the medaka fabp11b gene which may explain the retention of sister duplicates of fabp11 in the medaka genome.