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Molecular characterization of chicken SOCS2 gene

by Zhou, Gaoying

Abstract (Summary)
(Uncorrected OCR) Abstract of thesis entitled MOLECULAR CHARACTERIZATION OF CHICKEN SOCS2 GENE Submitted by Zhou Gaoying for the degree of Master of Philosophy at The University of Hong Kong in February 2005 Suppressor of cytokine signaling 2 (SOCS2), a member of SOCS family, negatively regulates cytokine signaling through the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. In mammals, SOCS2 is known to be induced by a wide range of cytokines and attenuate cytokine signaling with a negative feedback strategy. However, the detailed process is still unclear. In the present study, the genomic structure, mRNA expression and promoter of chicken SOCS2 gene were characterized in a chicken experimental model. Chicken SOCS2 gene contains two exons, resulting in two transcript variants. Studies of the variants showed that they had differential expression patterns in various tissues. In the primary culture of chicken hepatic cells, the SOCS2 gene could be induced by chicken growth hormone (cGH). To further elucidate the stimulatory effect of GH on the SOCS2 gene expression, the promoter region located within -1900 to -800 was investigated. In this region, two consecutive highly conserved motifs ?TCCTGGAA? previously known as mammary gland factor (MGF) boxes, were found to be closely associated with the transcriptional activity of the SOCS2 gene in response to GH and prolactin (PRL). Deletion of the motifs resulted in a loss of responsiveness to the hormones. Intriguingly, overexpression of chicken STAT5 but not STAT3, was able to mimic the stimulatory action of GH on the promoter of chicken SOCS2 gene, whereas the removal of the MGF boxes abolished the enhancing effect of STAT5. This strongly suggests that the MGF box may serve as a docking site for STAT5 to mediate the transcriptional activity of the SOCS2 gene. Overall, the results of this study provide direct evidence that STAT5 is likely to modulate the SOCS2 gene expression by interaction with the MGF boxes in response to the stimulation of GH.
Bibliographical Information:

Advisor:

School:The University of Hong Kong

School Location:China - Hong Kong SAR

Source Type:Master's Thesis

Keywords:chickens molecular genetics genetic regulation gene expression cytokines

ISBN:

Date of Publication:01/01/2005

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