Characterization of the novel duplicated PRLR gene at the late-feathering K locus in Lohmann chickens

Abstract

A partial duplication of the prolactin (PRL) receptor gene (designated as dPRLR) has been identified at the late-feathering (LF) K locus on chromosome Z of some chicken strains recently, implying that dPRLR is probably a candidate gene associated with LF development in chickens. However, little is known about the structure, functionality, and spatiotemporal expression of the dPRLR gene in chickens. In this study, using 3 0 -RACE and RT-PCR, the full-length cDNA of the dPRLR obtained from the kidneys of male Lohmann layer chickens carrying a K allele was cloned. The cloned dPRLR is predicted to encode a membranespanning receptor of 683 amino acids, which is nearly identical to the original PRLR, except for its lack of a 149-amino acid C-terminal tail. Using a 5! STAT5-Luciferase reporter system and western blot analysis, we demonstrated that dPRLR expressed in HepG2 cells could be potently activated by chicken PRL and functionally coupled to the intracellular STAT5 signaling pathway, suggesting that dPRLR may function as a novel receptor for PRL. RT-PCR assays revealed that similar to the original PRLR gene, dPRLR mRNA is widely expressed in all embryonic and adult tissues examined including the skin of male Lohmann chickens with a K allele. These findings, together with the expression of PRL mRNA detected in the skin of embryos at embryonic day 20 and 1-week-old chicks, suggest that skin-expressed dPRLR and PRLR, together with plasma and skin-derived PRL, may be involved in the control of the LF development of chicks at hatching. Moreover, the wide tissue expression of dPRLR implies that dPRLR may regulate other physiological processes of chickens carrying the K allele.

Molecular characterization of two suppressor of cytokine signaling 1 genes (SOCS1a and SOCS1b) in chickens

“…The amino acid sequences of SOCS1a or SOCS1b genes from other species were either retrieved from GenBank or predicted according to genomic sequences. their specific ligands can activate the JAK-STAT signaling pathway, as previously reported [22,24] . However, transient expression of cSOCS1a completely inhibited the stimulatory effect of cGH-or cPRL-induced luciferase activities of Hep G2 cells.…”

“…It has been reported that SOCS1 can negatively regulate GH or PRL signaling in mammals [15,16] , therefore, in this study, we also examined whether transient expression of cSOCS1a or cSOCS1b in Hep G2 cells can block cGH/ cPRL signaling using a 5 Â luciferase reporter system, which can sensitively monitor the receptor (cGHR or cPRLR)-activated JAK-STAT signaling pathway, as reported in previous studies [22,24] . As showed in Fig.…”

“…To test whether cSOCS1a and cSOCS1b proteins are capable of inhibiting cGH/cPRL signaling in vitro, cSOCS1a or cSOCS1b were transiently expressed in human hepatocellular carcinoma (Hep G2) cells expressing either cGHR or cPRLR, and the inhibitory action on cGHR-or cPRLR-mediated signaling evaluated by a 5 Â STAT5-luciferase reporter system established in previous studies, which have been shown to be capable of monitoring the receptor-activated JAK-STAT signaling pathway [22][23][24] . In brief, Hep G2 cells were maintained in DMEM supplemented with 10% fetal bovine serum, 100 U$mL -1 of penicillin G, and 100 mg$mL -1 of streptomycin (HyClone, Logan, UT, USA) in 48-well plate (Nunc, Rochester, NY, USA) incubated at 37°C with 5% CO 2 .…”

Functionally reciprocal mutations of the prolactin signalling pathway define hairy and slick cattle

“…These observations suggest enhanced prolactin pathway signalling as a result of the PRLR p.Leu462* mutation. An example of a functionally coupled, C-terminal PRLR mutant has recently been described in chickens, where, notably, this variant has been proposed as the causative mutation underlying a dominantly inherited feather-growth retardation phenotype 22 .…”

Copy Number Variation in Chickens: A Review and Future Prospects

“…Nonetheless, transcripts of the partial duplicated dPRLR were found in a wide array of tissues. Its encoded protein, a truncated version of PRLR lacking a 149-aa C-terminal tail, can be potently activated by prolatin [48], suggesting the duplicated PRLR may be involved in a wide range of physiological activities.…”