Molecular Cloning And Tissue Expression Analysis Of Zie Goose Clock MRNA Throughout The Reproductive Cycle

Circadian gene is a system that sets and regulates circadian rhythm in organisms, as an oscillation with an approximate 24-hour cycle. The center of circadian rhythm is located in the SCN, send information to control the whole body rhythm activity; and throughout the whole body tissue cells also exist in peripheral clocks, all kinds of gene and protein in cells and cyclical change, by nerves, body fluids, and other signal molecules on the adjustment of the environment. The core molecular mechanism of circadian rhythms is Clock gene, directly or indirectly regulate the other genes.Goose is a typical seasonal breeding poultry, adhere to non-breeding period, early laying period, peak period and later period in one year. In order to obtain the Clock gene of Zie goose, collecting the fresh tissue of hypothalamus and ovary to extract total RNA, then cloning the gene of Clock. The c DNA of Clock consisted of 3 112 bp, 2 574 bp CDS, encoding 857 amino acids. The deduced amino acid sequence of goose Clock is highly conserved with the sequence from other species, especially with chicken and ducks(94% and 98%). There are 3 domains, a b HLH DNA-binding, a PAS domain to promote protein-protein interaction and a glutamine-rich(Q-rich) transcription activation domain.To investigate the expression of hypothalamus Clock m RNA in different reproduction stages in Zie geese, the hypothalamus Clock m RNA level was tested by real-time fluorescence quantitative PCR method in eight geese at stages of non-breeding period(January), early laying period(March), peak period(April) and later period of laying(June), respectively. The CDS of Clock gene was obtained by q RT-PCR. The nucleotide sequence of CDS shared 94 % and 98 % consistency with the Clock gene of gallus and anas respectively. In hypothalamus and ovary, there were certain regularity. The m RNA levels of Clock gene in hypothalamus were variability from January to June. The level of hypothalamus Clock m RNA(0.02454± 0.01172) in peak period was significantly higher(P<0.05) than later period of laying(0.00205± 0.00061). But the Clock m RNA in later period was similar to early laying period(0.01223± 0.00462) and non-breeding period(0.01104± 0.00442). In ovary, there were certain regularity, similar to the hypothalamus. The level of ovary Clock m RNA(0.01990± 0.00302) in peak period was significant higher(P<0.01) than the other three periods. The Clock m RNA of non-breeding period(0.00416± 0.00098) was similar to the early laying period(0.00768± 0.00325) and the later period(0.00559± 0.00237).This research demonstrates the Clock gene expression in hypothalamus and ovary of Zie geese was related with the rhythm of ovulation in ovary. This result will give insight into the molecular mechanism of clock gene in regulating Zie geese reproductive trait.