| Fatty acid binding proteins (FABPs), a group of small molecular weight proteins with high binding affinities for fatty acids, are members of a superfamily of lipid-binding proteins, and occur intracellularly in vertebrates and invertebrates. FABPs are considered to be important carriers for the transportation of intracellular fatty acid. They transport fatty acids from the plasma membrane to sites of fatty acid oxidation, of fatty acid esterification into triacylglycerols or phospholipids, or to the nucleus for possible regulatory functions. Therefore, FABPs play an important role in the modulation of lipids metabolism. This study was designed to clone the chicken FABP gene based on the sequence of mammal FABP gene by comparative genome and bioinformatics approaches; to investigate the expression characterization of FABP genes by Northern blot and RT-PCR; to detect the polymorphisms of FABP genes by DNA sequencing, PCR-SSCP and PCR-RFLP methods, and to investigate the effects of FABP genes polymorphisms on growth and body composition traits in F2 population and divergent lines of lean and fat broilers. The main results are as follows:(1) The cDNA and genomic sequences of chicken A-FABP, H-FABP, I-FABP gene and the genomic sequence of chicken L-FABP gene were cloned. The overall organization of these genes is identical. They are consisted of four exons and three introns.(2) Northern blot analysis indicated that the chicken A-FABP gene expressed only in adipose among tested tissues from chickens of 2, 6 and 12 wk of age. The expression levels of the chicken A-FABP had no significant difference in adipose tissues between the male birds from fat line and Bai'er breed at 2, 6 and 12 wk of age. RT-PCR analysis indicated that the chicken A-FABP gene expressed only in adipose among tested tissues from chickens of 6 and 12 wk of age.(3) Northern blot analysis indicated that the chicken H-FABP expressed in many tissues, including brain, lung, muscle stomach, gland stomach, leg muscle, breast muscle, heart, ovary and adipose, from chickens of 2, 6 and 12 wk of age; The expression levels of the chicken A-FABP had significant difference in heart between the male birds from fat line and Bai'er breed at 2, 6 and 12 wk of age (P<0.05), however there was no no significant difference in fat tissues. RT-PCR analysis indicated that the chicken H-FABP expressed in all tested tissues from chickens of 6 and 12 wk of age.(4) Northern blot analysis indicated that the chicken I-FABP gene expressed only in intestineamong tested tissues from chickens of 2, 6 and 12 wk of age; The expression levels of chicken I-FABP had difference in intestine tissues between the male birds from fat line and Bai'er breed in 6 wk of age, and the expression level of the gene in fat broilers was significant lower than that of Bai'er breed (P<0.05). RT-PCR analysis indicated that the chicken I-FABP expressed in many tissues, including intestine, kidney, spleen, lung, heart, muscle stomach, gland stomach, leg muscle, breast muscle and ovary tissues, from chickens of 6 and 12 wk of age.(5) Northern blot analysis indicated the chicken L-FABP gene expressed only in liver and intestine among tested tissues from chickens of 2, 6 and 12 wk of age; The expression level of the chicken L-FABP in intestine tissues was significant different between the male birds at 6 wk of age from fat line and Bai'er breed (PO0.01). The difference of the gene expression level in liver between the male birds at 6 and 12 wk age from the two breeds was also observed. The expression level of the chicken L-FABP gene was significant lower in broilers than that of layers both in intestine and liver tissues (P<0.01). The expression level of the chicken L-FABP gene was significant different in liver tissues of 19-day embryo between the bkds from fat and lean lines, and the expression level of the gene in lean broiler was significant lower than that of fat ones (PO.05). In contrast, the expression level of L-FABP gene in liver of 10-day old lean.birds was significant higher than mat o... |
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