title: Comparative genomic and phylogenetic analyses of the intelectin gene family: implications for their origin and evolution.
abstract: Intelectin is a newly characterized gene family involved in early embryogenesis, host-pathogen interactions and iron metabolism. In this study, we searched the genomes of metazoans by extensive BLAST survey and found no intelectin homologs in invertebrate metazoans but 12 in amphioxus Branchiostoma floridae and 21 in ascidians Ciona intestinalis. Some ascidians oocyte cortical granule lectins (CGLs) have unknown insertion sequences between fibrinogen-related domain (FReD) and Intelectin Domain, the boundaries of which are equivalent to exon structures. In addition to ascidians intelectins/CGLs located in the base, phylogenetic tree comprises four main clades representing mammal, frog, fish, and amphioxus, indicating that intelectin genes undergo extensive lineage-specific duplication or gene conversion. However, genomic neighborhood surrounding analysis shows that clear proto-orthologies are difficult to be established among these counterparts. In addition, sequence comparison and phylogenetic analysis of FReDs from intelectins and other fibrinogen-like proteins from choanoflagellate, anemone, frog and human indicate FReDs of intelectins are unique. Likewise, these choanoflagellate and anemone genes may be close to intelectin gene.
authors: Marine Biotechnology Research Center, Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, Institute of Developmental Biology, School of Life Sciences, Shandong University, Jinan, Shandong 250100, PR China. yanjiesdu@gmail.com
authors: Jie
authors: J
authors: Yan
authors: Lingxiao
authors: L
authors: Xu
authors: Yan
authors: Y
authors: Zhang
authors: Changqing
authors: C
authors: Zhang
authors: Chao
authors: C
authors: Zhang
authors: Fei
authors: F
authors: Zhao
authors: Lijun
authors: L
authors: Feng
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001001:Anura / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D002816:Chordata, Nonvertebrate / Q000235:genetics; D002874:Chromosome Mapping; D002938:Ciona intestinalis / Q000235:genetics; D016207:Cytokines / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D005399:Fishes / Q000235:genetics; D058851:GPI-Linked Proteins / Q000145:classification / Q000235:genetics; D016678:Genome / Q000235:genetics*; D006801:Humans; D037102:Lectins / Q000145:classification / Q000235:genetics*; D008322:Mammals / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D013045:Species Specificity
chemical_list: D016207:Cytokines; D058851:GPI-Linked Proteins; C432397:ITLN1 protein, human; C484562:ITLN2 protein, human; D037102:Lectins
keywords: Comparative genomics; Evolution; FReD; Intelectin