Differential expression profiling of ovarian genes in prelaying and laying geese

The identification of the differential expression of genes in the ovaries of egg-laying and prelaying Zi geese is required to improve the laying performance of the geese. In the present study, suppression subtractive hybridization and reverse dot-blot were employed to identify such genes, using the ovary as a model. Furthermore, expression profiling of estrogen receptor 1, estrogen receptor 2, follicle stimulating hormone receptor, prolactin receptor, ferritin H chain, and ovary differentially expressed unknown gene 08 in ovaries from geese was performed by quantitative real-time PCR. Total RNA from the ovaries of laying and prelaying Zi geese was pooled and the mRNA was isolated. The cDNA that was reverse-transcribed from the ovarian mRNA of the prelaying geese was subtracted from the cDNA isolated from the laying geese. Four hundred sixty-five clones containing putative differentially expressed gene fragments were further identified by reverse dot-blot. Ninety-seven clones were subjected to sequencing and further analysis. Sequence analysis showed that the expression of 18 known (including a mitochondrial gene) and 8 unknown gene fragments was higher in the ovaries of laying geese compared with prelaying geese. Seventeen of the known genes encode proteins that belong to groups involved with binding, catalytic activity, enzyme regulatory activity, signal transducer activity, structural molecule, and transporter activity. The results of the quantitative real-time PCR showed that the expression of estrogen receptor 1, estrogen receptor 2, follicle stimulating hormone receptor, prolactin receptor, ferritin H chain, and ovary differentially expressed unknown gene 08 was higher in the ovaries of the laying geese than in those of the prelaying geese (P<0.05). These differentially expressed genes may be relevant to the progression of prelaying geese to the egg-laying stage. Further study is required to elucidate the molecular mechanism that controls egg-laying in geese, to improve the productivity of laying geese.