title: Molecular characterization and tissue-specific expression of invariant chain isoform in Muscovy Duck (Cairina moschata).
abstract: Invariant chain (Ii) isoform, through its thyroglobulin-like (Tg) domain, inhibits cysteine proteases during antigen presentation in vertebrates. In birds, the Ii of Muscovy Duck (MDIi) has 2 forms: MDIi-1 and MDIi-2 (MDIi isoform). To understand the genetic information and expression characteristics of MDIi-2, polymerase chain reaction, and bioinformatic analysis were performed for MDIi-2 from healthy adult Muscovy Duck. The full-length MDIi-2 cDNA sequence was found to be 1377-base pairs, encoding a 285-amino acid protein. MDIi-2 contains 63 amino acids with an insertion sequence in the Tg domain. MDIi-2 shares high identity (72.51-94.74%) with the same protein in other birds. The Tg domain of MDIi-2 is highly conserved and showed relatively high identity (96.83%) among all tested birds. The molecular structure of the Tg domain supports this conservation. MDIi-2 expression was measured in various tissues using real-time quantitative polymerase chain reaction. Similar to MDIi-1, MDIi-2 was detected in all tissues but at different levels. Higher expression level was observed in the spleen, intestinal mucosa, and bursa stipe (bursa of Fabricius stipe) than in other tissues. This suggests that MDIi-2, like MDIi-1, plays an essential role in all tissues and that its differential expression may be related to its functions in these tissues. The coexistence of 2 MDIi isoforms indicates that their functions are correlated in Muscovy Duck. This study improves the understanding of poultry immunology and may be used to improve measures to protect Muscovy Duck from disease.
authors.affiliation: School of Life Science, Fuyang Teachers' College of Anhui Province, Fuyang, China.
authors.forename: S J
authors.initials: SJ
authors.lastname: Liu
authors.affiliation: Key Laboratory of Zoonoses of Anhui Province, Anhui Agricultural University, Hefei, China.
authors.forename: F F
authors.initials: FF
authors.lastname: Chen
authors.affiliation: Key Laboratory of Zoonoses of Anhui Province, Anhui Agricultural University, Hefei, China.
authors.forename: C
authors.initials: C
authors.lastname: Wu
authors.affiliation: Key Laboratory of Zoonoses of Anhui Province, Anhui Agricultural University, Hefei, China.
authors.forename: Q S
authors.initials: QS
authors.lastname: Ni
authors.affiliation: Key Laboratory of Zoonoses of Anhui Province, Anhui Agricultural University, Hefei, China yuweiyi@ahau.edu.cn.
authors.forename: W Y
authors.initials: WY
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004372:Ducks / Q000235:genetics*; D020869:Gene Expression Profiling; D000949:Histocompatibility Antigens Class II / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013154:Spleen / Q000378:metabolism; D013950:Thymus Gland / Q000378:metabolism
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D000949:Histocompatibility Antigens Class II; D020033:Protein Isoforms; C045084:invariant chain; D004247:DNA