Infectious agents such as bacteria or viruses can grow rapidly. If a
microorganism invades a host, it must be recognized rapidly and destroyed before it
overwhelms the immune system. Limiting infection to a minimum in the early stage is
critical for the outcome and the recovery from infection. The innate immune system has
evolved to recognize a few highly conserved, constitutive structures present only in
microorganisms, such as bacterial lipopolysaccharide (LPS), called pathogen-associated
molecular patterns (PAMP). Toll-like receptors are the host receptors that recognize
PAMP, ultimately activating a variety of transcription factors to induce expression of a
wide spectrum of immune related genes, e.g. defensins. Defensins are antimicrobial
peptides that play an important role in innate defense against microorganisms in plants
and animals. Beta-defensins are the largest family of antimicrobial peptides, which can
directly kill microorganisms and have regulatory effects on the immune system.
Thirteen beta-defensins have been identified; however, the regulation of these genes has
not been well-investigated in the chicken. The objective of this research was to
understand constitutive and inducible gene expression of beta-defensins in chicken white
blood cells. Real-time RT-PCR was used to quantify gene expression level before and after LPS stimulation. Transcription factor binding sites in the genes were identified to
understand the gene expression regulation. From the expression profile results, most
chicken beta-defensins had induced gene expression by LPS stimulation in the early
phase (0- to 3-hour) and reduced gene expression in the late phase (3- to 8-hour). As for
the level of gene expression, the results show that the induced gene expression in the
early phase corresponded to the higher levels of expression at 3-hours after LPS
stimulation, and the reduced gene expression in the late phase corresponded to the lower
levels of gene expression at 8-hours after LPS stimulation.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1849 |
| Date | 02 June 2009 |
| Creators | Supak, Tiffany Marie |
| Contributors | Berghman, Luc, Zhu, James |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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