Comparative proteomic analysis of pituitary glands from Huoyan geese between pre-laying and laying periods using an iTRAQ-based approach

Abstract

In this study, we performed a comprehensive evaluation of the proteomic profile of the pituitary gland of the Huoyan goose during the laying period compared to the pre-laying period using an iTRAQ-based approach. Protein samples were prepared from pituitary gland tissues of nine pre-laying period and nine laying period geese. Then the protein samples from three randomly selected geese within each period were pooled in equal amounts to generate one biological sample pool. We identified 684 differentially expressed proteins, including 418 up-regulated and 266 down-regulated proteins. GO annotation and KEGG pathway analyses of these proteins were conducted. Some of these proteins were found to be associated with hormone and neurotransmitter secretion and transport, neuropeptide signalling and GnRH signalling pathways, among others. Subsequently, the modification of the abundance of three proteins (prolactin, chromogranin-A and ITPR3) was verified using western blotting. Our results will provide a new source for mining genes and gene products related to the egg-laying performance of Huoyan geese, and may provide important information for the conservation and utilization of local goose breeds.

Fig 1. Experimental design and schematic diagram of the workflow used in this study.

Fig 2. Unique peptides for the identified proteins.

The number of proteins in each category is presented at the top of each bar.

Fig 3. Gene Ontology (GO) cellular component analysis of the differentially expressed proteins in the pituitary gland.

All data are presented on the basis of GO second-level terms. Numbers refer to assigned proteins in each category.

Fig 4. Gene Ontology (GO) molecular function analysis of the differentially expressed proteins in the pituitary gland.

All data are presented on the basis of GO second-level terms. Numbers refer to assigned proteins in each category.

Fig 5. Gene Ontology (GO) biological process analysis of the differentially expressed proteins in the pituitary gland.

All data are presented on the basis of GO second-level terms. Numbers refer to assigned proteins in each category.

Fig 6. Distribution of KEGG pathways in the pituitary proteome.

Fig 7. Western blot analysis of prolactin, chromogranin-A and ITPR3 in the pituitary tissues of Huoyan geese between pre-laying and laying periods.

GAPDH was used as the internal control. Protein band density was analysed using the GelQuant software. Upper panels: representative immunoblots. Lower panels: densitometric analysis of prolactin, chromogranin-A and ITPR3 protein relative to GAPDH protein. Values are expressed as the means±SEM of the mean in arbitrary optical density units (AU).