Spexin(SPX1)是14个氨基酸(aa)的神经肽,最初由生物信息学鉴定,通过甘丙肽受体2和3(GALR2/3)参与脊椎动物的各种生理功能。为了阐明SPX1在控制黄尾金鱼繁殖中的生物学作用,它被认为是世界上近海水产养殖的有前途的物种,在本研究中鉴定了spx1和六个潜在受体的cDNA序列。黄尾金鱼spx1的开放阅读框为363个核苷酸,编码120-aa的前激素,它的成熟肽在其他物种中高度保守。六个GALR(galr1a,galr1b,galr2a,galr2b,Galr1型和Galr2型)为1053个碱基对(bp),1068bp,981bp,1137bp,1038bp,924bp,编码350个氨基酸的G蛋白偶联受体,355aa,326aa,378aa,345aa,307aa,分别。组织分布分析表明,spx1,galr1b,galr2b转录本主要在大脑中检测到。在垂体中观察到galr1a和galr2a的最高mRNA水平,其次是大脑和卵巢.Galr1型和Galr2型在各种组织中广泛表达,肾脏有一个峰值水平。此外,所有spx1和galr基因在早期个体发育过程中显著波动,表现出不同的表达方式。腹腔注射SPX1显著增加脑gnrh1、gnih、spx1,gal,和tac3表达式,虽然它抑制了gnrh2,kiss1r,和kiss2rmRNA水平。在垂体里,SPX1注射降低了gh的转录水平,lhβ,和fshβ。总的来说,我们的结果表明,SPX1参与了黄尾金鱼的生殖功能。
Spexin (SPX1) is a neuropeptide of 14 amino acids (aa), originally identified by bioinformatics, which has been implicated in various physiological functions in vertebrates via galanin receptors 2 and 3 (GALR2/3). To clarify the biological role of SPX1 in the control of reproduction in yellowtail kingfish, which is regarded as a promising species for offshore aquaculture worldwide, cDNA sequences of spx1 and six potential receptors were identified in the current study. The open reading frame of yellowtail kingfish spx1 was 363 nucleotides in size that encoded a 120-aa preprohormone, and its mature peptide was highly conserved among other species. The cDNA sequences of six GALRs (galr1a, galr1b, galr2a, galr2b, galr type 1, and galr type 2) were 1053 base pairs (bp), 1068 bp, 981 bp, 1137 bp, 1038 bp, 924 bp, which encoded G protein-coupled receptors of 350 aa, 355 aa, 326 aa, 378 aa, 345 aa, 307 aa, respectively. Tissue distribution analysis showed that spx1, galr1b, and galr2b transcripts were mainly detected in the brain. The highest mRNA levels of galr1a and galr2a were observed in the pituitary, followed by the brain and ovary. Both galr type 1 and galr type 2 were widely expressed in various tissues, with a peak level in the kidney. Moreover, all spx1 and galr genes significantly fluctuated during early
ontogeny, exhibiting different expression patterns. Intraperitoneal injection of SPX1 significantly increased brain gnrh1, gnih, spx1, gal, and tac3 expression, while it inhibited gnrh2, kiss1r, and kiss2r mRNA levels. In the pituitary, SPX1 injection reduced transcript levels of gh, lhβ, and fshβ. Overall, our results have revealed the involvement of SPX1 in the reproductive functions in yellowtail kingfish.