Cloning and expression of the elk (Cervus elaphus) pituitary glycoprotein hormones
Date
2004-11-26
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Degree Level
Masters
Abstract
The North American elk or wapiti is an indigenous species to Canada. Understanding of the reproductive physiology of elk is limited, as little research has been conducted in this field as compared to domestic farmed species. In order to make available the tools to study reproductive physiology of the elk this thesis describes the cloning and expression of elk pituitary glycoprotein hormone cDNAs. The common gonadotropin a-subunit, and FSH, LH and TSH b-subunit elk cDNAs were amplified by reverse transcription and polymerase chain reaction (RT-PCR). There was a high degree of nucleotide similarity between the elk a and b subunits when compared with reported sequences from other species. The cDNAs for the pituitary glycoprotein hormone genes were used as probes to investigate seasonal expression in the female elk pituitary gland. Steady state levels of the common a-subunit mRNA was observed regardless of the reproductive season, but a significant increase in expression occurred during the breeding season. The FSH and LH b-subunit genes were expressed at low levels in pituitary glands of animals during presumed anestrous and pregnancy, but levels considerably increased during estrus. In contrast, levels of TSH b-subunit mRNA were similar regardless of the reproductive status. The FSH cDNAs were also transfected into a Chinese hamster ovary (CHO) mammalian expression system, aimed at the production of recombinant elk FSH. Transfected CHO cell lines were screened for expression of a- and FSH b-subunit mRNA by Northern blot. Activity of FSH was equivalent to ~100 mIU/ml of recombinant human FSH (Gonal-FTM), identified by FSH receptor signaling in an in vitro cell based assay. In conclusion, this work represents an advance towards understanding the molecular basis of seasonal reproduction in elk. This information and the availability of elk recombinant FSH will be useful for the application of advanced reproductive technologies required for the rapid expansion of healthy, disease resistant, and genetically superior animals, which are important for domestic production and wildlife management.
Description
Keywords
gene, RT-PCR, cloning, elk, cervid
Citation
Degree
Master of Science (M.Sc.)
Department
Veterinary Biomedical Sciences
Program
Veterinary Biomedical Sciences