A cellular retinoic acid-binding protein from zebrafish (Danio rerio): cDNA sequence, phylogenetic analysis, mRNA expression, and gene linkage mapping.
We report the sequence of a cDNA clone coding for a cellular retinoic acid-binding protein (CRABP) in zebrafish. The encoded polypeptide is 142 amino acids in length with an estimated molecular mass of 15.8 kDa and a calculated isoelectric point of 5.2. The zebrafish CRABP exhibits highest sequence identity to the pufferfish CRABPIIa (83%) and CRABPIIb (79%), and human CRABPII (74%) than to any other member of the intracellular lipid-binding protein (ILBP) family. A phylogenetic tree for different members of the ILBP multigene family including fatty acid-binding proteins (FABPs), cellular retinol-binding proteins (CRBPs) and CRABPs shows that the cloned zebrafish cDNA encodes a protein that clusters with CRABPs from other species and not with CRBPs and FABPs. Reverse-transcription polymerase chain reactions (RT-PCR), using oligonucleotide primers specific to the zebrafish CRABP cDNA made from total RNA of embryos collected at various developmental stages, did not detect the CRABP mRNA until 12 h post-fertilization. In adult zebrafish, CRABP mRNA was detected by RT-PCR in total RNA extracted from muscle, testes and skin, barely detectable in heart, ovary and brain and undetectable in liver, kidney and intestine. Quantitative RT-PCR (qRT-PCR) revealed a similar tissue-specific distribution for zebrafish CRABP mRNA with highest levels of CRABP mRNA in muscle followed by testes, skin, ovary and much lower levels in heart. Radiation hybrid mapping assigned the CRABP gene to linkage group 16 in the zebrafish genome. Comparison of the mapped zebrafish CRABP and human CRABPII genes revealed that zebrafish linkage group 16 has a syntenic relationship with human chromosome 1. Based on phylogenetic analysis and the syntenic relationship to the CRABPII gene in human, the zebrafish cDNA clone appears to code for a type II CRABP.
Sharma
Mukesh K
MK
Department of Biology, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada.
Denovan-Wright
Eileen M
EM
Boudreau
Mary Ellen R
ME
Wright
Jonathan M
JM
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development; D005260:Female; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D021101:Radiation Hybrid Mapping; D018168:Receptors, Retinoic Acid / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D026801:Synteny; D015027:Zebrafish / Q000196:embryology / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics*
D018076:DNA, Complementary; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; D029961:Zebrafish Proteins; C082927:retinoic acid binding protein I, cellular; C082928:retinoic acid binding protein II, cellular