Association of polymorphisms in the promoter region of turkey prolactin with egg performance

The induction and regulation of broodiness is of the most important role of prolactin in avian species. In this study, the association between prolactin promoter region alleles and reproductive traits in Fars native turkey was investigated. These traits consisted of mean egg weight (MEW), number of egg (EN) and egg mass, during the first laying period. In total, 115 laying turkeys, randomly selected from the flock of the Breeding Center for Fars Native turkey, and DNA was purificated from blood samples, 231 bp of prolactin promoter region was amplified and Genotype of Samples was determinate by PCR-SSCP technique were genotyped. Two alleles D and I were identified. Based on the results obtained, the frequency of D and I alleles were 0.67 and 0.33, respectively. Frequencies of DD, II and ID genotypes were 0.385, 0.044 and 0.571, respectively. The association analysis between the polymorphism PRL gene promoter region and egg performance was carried out. Significant relationship was found between genotypes with egg production (P<0.01). Individuals with II genotype produced higher egg production than DD and ID genotype. The results of current study showed that using information of genes related to egg production could be used to improve the performance of native turkey of East Azerbaijan province.

The gsp Oncogene Disrupts Ras/ERK-Dependent Prolactin Gene Regulation in gsp Inducible Somatotroph Cell Line

The MAPK ERK1/2 cascade regulates all the critical cellular functions, and in many pathological situations, these regulatory processes are perturbed. It has been clearly established that this cascade is an integrative point in the control of the pituitary functions exerted by various extracellular signals. In particular, ERK1/2 cross talk with the cAMP pathway is determinant in the control of somatolactotroph hormonal secretion exerted via neuropeptide receptors. GH-secreting adenomas are characterized by frequent cAMP pathway alterations, such as constitutive activation of the α-subunit of the heterotrimeric Gs protein (the gsp oncogene), overexpression of Gsα, and changes in the protein kinase A regulatory subunits. However, it has not yet been established exactly how these alterations result in GH-secreting adenomas or how the ERK1/2 cascade contributes to the process of GH-secreting adenoma tumorigenesis. In this study on the conditional gsp-oncogene-expressing GH4C1 cell line, expression of the gsp oncogene, which was observed in up to 40% of GH-secreting adenomas, was found to induce sustained ERK1/2 activation, which required activation of the protein kinase A and the GTPases Ras and Rap1. All these signaling components contribute to the chronic activation of the human prolactin promoter. The data obtained here show that Ras plays a crucial role in these processes: in a physiopathological context, i.e. in the presence of the gsp oncogene, it switched from being a repressor of the cAMP/ protein kinase A ERK-sensitive prolactin gene control exerted by neuropeptides to an activator of the prolactin promoter.