Gene Expression Of Chicken CLOCK Gene In Response To Campylobacter Jejuni Infection And Its Polymorphism Analysis

The CLOCK gene as one of the core gene regulation of circadian rhythms phenomenonplays a key role in the maintenance of normal circadian rhythm and body homeostasis.Campylobacter jejuni (C. jejuni) as the human food born pathogenic bacteria, the WorldHealth Organization has been listed as one of the most common source of food borne diseases.In order to study the CLOCK gene polymorphism and CLOCK gene regulation in chickenafter infected Campylobacter jejuni. The research from the molecular level to study thegenetic variations of the CLOCK gene, expression in different tissues and differentialexpression Campylobacter jejuni infected chicken, so as to give some advices to chickendisease resistance breeding.In this study, genetic variations of360individuals including six breeds (AA, Hy-LineBrown, Shouguang, Jiningbairi, Wenshangluhua, Dou breed) were detected using directsequencing techniques. The sequencing results showed that there are five polymorphic loci inexon, including4synonymous variant and1deletion, variant in exon18of the newlydiscovered. According to the results were genotyped six breeds found out the genotypes hadthe different distribution in six breeds.SPF chickens and Jining Bairi chickens were used of1day old and divide them intoinfected and non-infected groups in animal testing. Infected groups orally inoculated with500μl of the Campylobacter jejuni suspension containing108cfu/ml at3days old, at the sametime non-infected groups injected with500ul PBS. Take spleen and cecal was measuredCLOCK gene mRNA expression and the cecal contents was measured Campylobacterpositive rate and counted at hour4,8,12,16,20,24and48post infection. Results show that(1) Non-infected groups the bacterial tested negative, Jining Bairi infected groups werepositive and SPF chickens infected groups positive first declined and then increased. TheCampylobacter jejuni were gradually decreased in Jining Bairi infected groups. (2) The infected groups and the non-infected groups CLOCK gene mRNA expression inthe cecal and spleen difference significantly or extremely significant (P <0.05) at all the timepost inoculation except Jining Bairi cecal.(3) The non-infected groups CLOCK gene mRNA expression in the cecal differencesignificantly or extremely significant (P <0.05) at hour8,12,20,24and48post inoculationbetween the two chicken breeds. The infected groups CLOCK gene mRNA expression in thececal difference significantly or extremely significant (P <0.05) at hour4,8,12,16and24post inoculation between the two chicken breeds.(4) The non-infected groups CLOCK gene mRNA expression in the cecal differencesignificantly or extremely significant (P <0.05) at hour4,8,12,20,24and48post inoculationbetween the two chicken breeds. The infected groups CLOCK gene mRNA expression in thececal difference significantly or extremely significant (P <0.05) at hour4,8,12and16postinoculation between the two chicken breeds.(5) CLOCK gene mRNA expression in the cecal tissue was significantly higher than theexpression in the spleen tissue (P <0.01).These results indicated that the CLOCK gene have more expression in cecal than spleenand the CLOCK gene plays an important role in the process of Campylobacter jejuni infectedchickens. The CLOCK gene have different expression between SPF chicken and Jining Bairichicken after inoculation.