Relaxin-1 mRNA and relaxin-3 peptide expression in goldfish (Carassius auratus)
LE3 .A278 2005
Bachelor of Science
Relaxin-1 and relaxin-3 are polypeptide hormones of the relaxin-like peptide family and are expressed in most vertebrate species. Relaxin-1 is poorly conserved across species and exhibits pleiotropic effects. Relaxin-3, which has low sequence homology to relaxin but a high sequence homology across species, is expressed predominantly in the brain and is widely hypothesized to be an important neuropeptide. The purpose of this study was to investigate the presence of relaxin-1 and relaxin-3 in goldfish (Carassius auratus), specifically in brain, gill, heart, kidney, liver, gut, and gonad tissue. Northern Blot analysis was performed to investigate the expression of relaxin-1 mRNA transcripts. Western Blot analysis was performed to analyze relaxin-3 peptide expression. For Northern Blot analysis, nylon membranes were probed with tammar wallaby relaxin-1 cDNA probe. For Western Blot analysis, protein extracted from the tissues were separated by SDS-PAGE and blotted onto nitrocellulose membranes. The membranes were incubated with rabbit anti-human relaxin-3 antibody and subsequently with goat anti-rabbit antibody. Prepared membranes from both Northern and Western Blot analyses were labelled with chemiluminescent substrate and exposed to film. Northern Blot analysis was inconclusive; postulated to be due to low sequence homology between tammar wallaby and goldfish relaxin-1 or the absence of relaxin-1 mRNA transcripts in goldfish tissues. Western Blot analysis indicated that relaxin-3 protein was expressed in brain, gut, and possibly gonad tissue of a female goldfish. The presence of relaxin-3 in both teleosts and mammals suggests that relaxin-3 may be the ancestral relaxin-like peptide. Further study of both relaxin-like peptides and their interaction with specific receptors will aid in determining the many biological roles of relaxin-like peptides.
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