Identification and gene expression analysis of three GnRH genes in female Atlantic cod during puberty provides insight into GnRH variant gene loss in fish

Transcript levels of the soluble sperm factor protein phospholipase C zeta 1 (PLCζ1) increase through induced spermatogenesis in European eel

“…Total RNA was extracted following the method used by Hildahl et al (2011). Total RNA was treated with DNase I (Turbo DNA-free; Ambion) at 37°C for 30 min.…”

Differential regulation of GnRH ligand and receptor genes in the brain and pituitary of Atlantic cod exposed to different photoperiod

“…RNA was isolated from frozen tissues using the FastPrep FP220A instrument (MP Biomedicals, OH, USA) according to product specifications and as described previously [15,16]. Briefly, tissue was homogenized in tubes containing Trizol (Invitrogen, Paisley, United Kingdom) and lysing Matrix D (MP Biomedicals).…”

“…Gene expression analysis was performed as previously described for Atlantic cod GnRH2, GnRH3, GnRH-R1b, GnRH-R2a, GnRH-R2b and GnRH-R2c [15,16]. Briefly, qPCR was performed on a LightCycler 480 Real-Time PCR system (Roche, Mannheim, Germany) using SYBR Green I detection (Roche).…”

“…pejerrey (Odontesthes bonariensis) [13] and black porgy (Acanthopagrus schlegeli) [25] during the spawning season. The observation that GnRH-R2a gene expression increases already in late-vitellogenesis compared to brain GnRH3, the likely hypophysiotrophic ligand in cod [16], which increases first in spawning fish, suggests that ligand tissue sensitivity precedes ligand availability such that the system is primed to respond when the conditions are appropriate. Likewise, GnRH-R2a increased gene expression precedes increased GnRH3 gene expression in the delayed sexual maturation of LL-NL fish.…”

“…Atlantic cod (Gadus morhua) possess three GnRH genes and four GnRH-R genes [15,16], however, one of the ligand genes (GnRH1) appears to be a pseudogene in the process of gene loss [16]. Gene expression studies indicate that there has been a functional shift in cod such that GnRH3 is the hypophysiotrophic form in cod, compensating for the loss of GnRH1.…”