The identification and expression of an interleukin-21 receptor in large yellow croaker (Larimichthys crocea)

• Published in: Molecular biology reports Vol. 50; no. 12; pp. 10121 - 10129
• Main Authors: Wu, Hanyu, Fu, Qiuling, Teng, Yan, Mu, Pengfei, Chen, Jingjie, Chen, Xinhua
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-12-2023; Springer Nature B.V
• Subjects: Amino Acid Sequence; Animal Anatomy; Animal Biochemistry; Animals; Bacterial Vaccines; Biomedical and Life Sciences; Evolutionary conservation; Fibronectin; Fish Proteins - metabolism; Gene expression; Gene Expression Regulation; Genomes; Glycosylation; Histology; Humans; Immune response; Interleukin 21; Kidneys; Larimichthys crocea; Leukocytes; Life Sciences; Morphology; Open reading frames; Original Article; Peptides; Perciformes - metabolism; Phylogeny; Polyinosinic:polycytidylic acid; Receptors, Interleukin-21 - genetics; Receptors, Interleukin-21 - metabolism; Structure-function relationships; Vaccines; IL-21; Immune response; Larimichthys crocea; IL-21R
• ISSN: 0301-4851; 1573-4978
• DOI: 10.1007/s11033-023-08827-1

Background
We identified a homologue of
IL-21R
(
LcIL-21R
) in large yellow croaker (
Larimichthys crocea
,
Lc
). Our investigation focused on understanding the molecular structural features and immune function of
LcIL-21R.
Methods
We cloned the
LcIL-21
R gene from the genome of
Larimichthys crocea
by RT‒PCR, and the molecular and structural characteristics of
LcIL-21R
were analyzed by a series of protein analysis tools. We used real-time PCR to investigate the tissue distribution of
LcIL-21
R, and
LcIL-21
R gene expression regulation was also measured in head kidney leukocytes under trivalent bacterial vaccine or poly (I:C) stimulation.
Results
The open reading frame (ORF) of the
LcIL-21
R gene is 1629 bp long and encodes a precursor protein of 542 amino acids (aa), with a 23-aa signal peptide and a 519-aa mature peptide containing four putative N-glycosylation sites.
LcIL-21
R has two fibronectin type III (FNIII)-like domains (D1 and D2), a transmembrane domain, and a cytoplasmic region. A conserved WSXWS motif was also found in the D2 domain. The predicted structure of the extracellular region of
LcIL-21
R (
LcIL-21
R-Ex) is highly similar to that of human IL-21R.
LcIL-21
R was constitutively expressed in all tissues examined, and
LcIL-21
R mRNA levels were increased in the head kidney and spleen upon inactivated trivalent bacterial vaccine or poly(I:C) stimulation.
Conclusions
Our results suggest that
LcIL-21R
shares structural and functional properties with
IL-21R
s found in other vertebrates, indicating its potential involvement in the IL-21-mediated immune response to pathogenic infections. These findings contribute to our understanding of the evolutionary conservation of IL-21 signaling and its role in the immune system.