TY - JOUR
T1 - Phylogeny and regulation of four lipocalin genes clustered in the chicken genome
T2 - Evidence of a functional diversification after gene duplication
AU - Pagano, Aldo
AU - Giannoni, Paolo
AU - Zambotti, Adriana
AU - Sánchez, Diego
AU - Ganfornina, Maria Dolores
AU - Gutiérrez, Gabriel
AU - Randazzo, Nadia
AU - Cancedda, Ranieri
AU - Dozin, Beatrice
PY - 2004/4/28
Y1 - 2004/4/28
N2 - A novel lipocalin gene is here reported that represents the fourth member of a cluster we have identified in the chicken genome. This cluster also includes Chondrogenesis-Associated Lipocalins β and γ (CALβ, CALγ) and Extracellular Fatty Acid Binding Protein (Ex-FABP). The new gene codes for a 22-kDa secreted protein with three cysteine residues and a series of sequence features well conserved in the lipocalin family. All the genes in the cluster are structurally similar presenting comparable exon/intron boundary positions and exon sizes. A phylogenetic analysis indicates the monophyletic grouping of these genes, and their relationship with the lipocalins α-1-microglobulin (A1mg), complement factor 8γ chain (C8GC), prostaglandin D synthase (PGDS), and neutrophil-gelatinase-associated lipocalin (NGAL). The new cluster gene appears to be the ortholog of the mammalian C8GC and was thus named Ggal-C8GC. This orthology also suggests that this lipocalin was present in the ancestor common to reptiles and mammals. In addition to other expressing tissues, Ex-FABP, CALβ and CALγ genes are highly transcribed in chondrocytes at late stages of chondrogenesis during endochondral bone formation and/or upon inflammatory stimulation. Here, we show that they are also transcriptionally induced when chondrocytes are subjected to various biological events as cell quiescence, cell shape transition, and hormonal stimulation. By contrast, Ggal-C8GC transcripts are only barely detectable in chondrocytes, but are more abundant in liver, kidney, brain, heart, skeletal muscle and particularly in skin. Moreover, no expression induction was observed neither during chondrocyte differentiation, nor upon any of the stimulations mentioned above. This indicates that the Ggal-C8GC gene was co-opted for a novel function after the duplication events that gave rise to the cluster. The peculiar coordinated regulation of Ex-FABP, CALβ and CALγ, and the apparent divergent role of Ggal-C8GC suggest that these gene duplications may have been maintained during evolution by a sub-functionalization mechanism where some common function(s) are shared by several members of the cluster and some other specialized function(s) are unique to other members.
AB - A novel lipocalin gene is here reported that represents the fourth member of a cluster we have identified in the chicken genome. This cluster also includes Chondrogenesis-Associated Lipocalins β and γ (CALβ, CALγ) and Extracellular Fatty Acid Binding Protein (Ex-FABP). The new gene codes for a 22-kDa secreted protein with three cysteine residues and a series of sequence features well conserved in the lipocalin family. All the genes in the cluster are structurally similar presenting comparable exon/intron boundary positions and exon sizes. A phylogenetic analysis indicates the monophyletic grouping of these genes, and their relationship with the lipocalins α-1-microglobulin (A1mg), complement factor 8γ chain (C8GC), prostaglandin D synthase (PGDS), and neutrophil-gelatinase-associated lipocalin (NGAL). The new cluster gene appears to be the ortholog of the mammalian C8GC and was thus named Ggal-C8GC. This orthology also suggests that this lipocalin was present in the ancestor common to reptiles and mammals. In addition to other expressing tissues, Ex-FABP, CALβ and CALγ genes are highly transcribed in chondrocytes at late stages of chondrogenesis during endochondral bone formation and/or upon inflammatory stimulation. Here, we show that they are also transcriptionally induced when chondrocytes are subjected to various biological events as cell quiescence, cell shape transition, and hormonal stimulation. By contrast, Ggal-C8GC transcripts are only barely detectable in chondrocytes, but are more abundant in liver, kidney, brain, heart, skeletal muscle and particularly in skin. Moreover, no expression induction was observed neither during chondrocyte differentiation, nor upon any of the stimulations mentioned above. This indicates that the Ggal-C8GC gene was co-opted for a novel function after the duplication events that gave rise to the cluster. The peculiar coordinated regulation of Ex-FABP, CALβ and CALγ, and the apparent divergent role of Ggal-C8GC suggest that these gene duplications may have been maintained during evolution by a sub-functionalization mechanism where some common function(s) are shared by several members of the cluster and some other specialized function(s) are unique to other members.
KW - α-1-microglobulin
KW - A1mg
KW - C8GC
KW - CAL
KW - Chondrogenesis- associated lipocalin
KW - Complement factor 8γ chain
KW - Evolution
KW - Ex-FABP
KW - Extracellular fatty acid binding protein
KW - Gene structure
KW - NGAL
KW - PGDS
KW - Prostaglandin D synthase
KW - Transcription regulation
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UR - http://www.scopus.com/inward/citedby.url?scp=16544364808&partnerID=8YFLogxK
U2 - 10.1016/j.gene.2004.02.001
DO - 10.1016/j.gene.2004.02.001
M3 - Article
C2 - 15094195
AN - SCOPUS:16544364808
VL - 331
SP - 95
EP - 106
JO - Gene
JF - Gene
SN - 0378-1119
IS - 1-2
ER -