title: Evidence of IgY subclass diversification in snakes: evolutionary implications.
abstract: Mammalian IgG and IgE are thought to have evolved from IgY of nonmammalian tetrapods; however, no diversification of IgY subclasses has been reported in reptiles or birds, which are phylogenetically close to mammals. To our knowledge, we report the first evidence of the presence of multiple IgY-encoding (υ) genes in snakes. Two υ genes were identified in the snake Elaphe taeniura, and three υ genes were identified in the Burmese python (Python molurus bivittatus). Although four of the υ genes displayed a conventional four-H chain C region exon structure, one of the υ genes in the Burmese python lacked the H chain C region 2 exon, thus exhibiting a structure similar to that of the mammalian γ genes. We developed mouse mAbs specific for the IgY1 and IgY2 of E. taeniura and showed that both were expressed in serum; each had two isoforms: one full-length and one truncated at the C terminus. The truncation was not caused by alternative splicing or transcriptional termination. We also identified the μ and δ genes, but no α gene, in both snakes. This study provides valuable clues for our understanding of Ig gene evolution in tetrapods.
authors.affiliation: State Key Laboratory of Agrobiotechnology, College of Biological Sciences, National Engineering Laboratory for Animal Breeding, China Agricultural University, Beijing 100094, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Yi
authors.initials: Y
authors.lastname: Sun
authors.forename: Wenwei
authors.initials: W
authors.lastname: Shao
authors.forename: Gang
authors.initials: G
authors.lastname: Cheng
authors.forename: Lingxiao
authors.initials: L
authors.lastname: Li
authors.forename: Zubing
authors.initials: Z
authors.lastname: Cao
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Huiying
authors.initials: H
authors.lastname: Zou
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Binyue
authors.initials: B
authors.lastname: Han
authors.forename: Yang
authors.initials: Y
authors.lastname: Hu
authors.forename: Liming
authors.initials: L
authors.lastname: Ren
authors.forename: Xiaoxiang
authors.initials: X
authors.lastname: Hu
authors.forename: Ying
authors.initials: Y
authors.lastname: Guo
authors.forename: Jing
authors.initials: J
authors.lastname: Fei
authors.forename: Lennart
authors.initials: L
authors.lastname: Hammarström
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Yaofeng
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000818:Animals; D000916:Antibody Diversity / Q000276:immunology*; D017821:Boidae / Q000276:immunology*; D019143:Evolution, Molecular; D007136:Immunoglobulins / Q000096:biosynthesis / Q000145:classification*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: C016512:IgY; D007136:Immunoglobulins