Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish

<p>Abstract</p> <p>Background</p> <p>Although unsaturated fatty acids such as eicosapentaenoic acid (EPA, C20:5n-3), docosahexaenoic acid (DHA, C22:6n-3) and arachidonic acid (ARA, C20:4n-6), collectively known as the highly unsaturated fatty acids (HUFA), play pivotal...

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Main Authors: Enyu Yee-Ling, Jaya-Ram Annette, Khong Hou-Keat, Tan Sze-Huey, Ishak Sairatul D, Kuah Meng-Kiat, Shu-Chien Alexander
Format: Article
Language:English
Published: BMC 2008-11-01
Series:Reproductive Biology and Endocrinology
Online Access:http://www.rbej.com/content/6/1/56
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author Enyu Yee-Ling
Jaya-Ram Annette
Khong Hou-Keat
Tan Sze-Huey
Ishak Sairatul D
Kuah Meng-Kiat
Shu-Chien Alexander
author_facet Enyu Yee-Ling
Jaya-Ram Annette
Khong Hou-Keat
Tan Sze-Huey
Ishak Sairatul D
Kuah Meng-Kiat
Shu-Chien Alexander
author_sort Enyu Yee-Ling
collection DOAJ
description <p>Abstract</p> <p>Background</p> <p>Although unsaturated fatty acids such as eicosapentaenoic acid (EPA, C20:5n-3), docosahexaenoic acid (DHA, C22:6n-3) and arachidonic acid (ARA, C20:4n-6), collectively known as the highly unsaturated fatty acids (HUFA), play pivotal roles in vertebrate reproduction, very little is known about their synthesis in the ovary. The zebrafish (Danio rerio) display capability to synthesize all three HUFA via pathways involving desaturation and elongation of two precursors, the linoleic acid (LA, C18:2n-6) and linolenic acid (LNA, C18:3n-3). As a prerequisite to gain full understanding on the importance and regulation of ovarian HUFA synthesis, we described here the mRNA expression pattern of two enzymes; desaturase (fadsd6) and elongase (elovl5), involved in HUFA biosynthesis pathway, in different zebrafish ovarian follicle stages. Concurrently, the fatty acid profile of each follicle stage was also analyzed.</p> <p>Methods</p> <p>mRNA levels of fadsd6 and elovl5 in different ovarian follicle stages were determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assays. For analysis of the ovarian follicular fatty acid composition, gas chromatography was used.</p> <p>Results</p> <p>Our results have shown that desaturase displayed significant upregulation in expression during the oocyte maturation stage. Expression of elongase was significantly highest in pre-vitellogenic follicles, followed by maturation stage. Fatty acid composition analysis of different ovarian follicle stages also showed that ARA level was significantly highest in pre-vitellogenic and matured follicles. DHA level was highest in both late vitellogenic and maturation stage.</p> <p>Conclusion</p> <p>Collectively, our findings seem to suggest the existence of a HUFA synthesis system, which could be responsible for the synthesis of HUFA to promote oocyte maturation and possibly ovulation processes. The many advantages of zebrafish as model system to understand folliculogenesis will be useful platform to further elucidate the regulatory and mechanism aspects of ovarian HUFA synthesis.</p>
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spelling doaj.art-e76ed7060a5f47679ce5e5ca463fad132022-12-22T00:37:01ZengBMCReproductive Biology and Endocrinology1477-78272008-11-01615610.1186/1477-7827-6-56Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafishEnyu Yee-LingJaya-Ram AnnetteKhong Hou-KeatTan Sze-HueyIshak Sairatul DKuah Meng-KiatShu-Chien Alexander<p>Abstract</p> <p>Background</p> <p>Although unsaturated fatty acids such as eicosapentaenoic acid (EPA, C20:5n-3), docosahexaenoic acid (DHA, C22:6n-3) and arachidonic acid (ARA, C20:4n-6), collectively known as the highly unsaturated fatty acids (HUFA), play pivotal roles in vertebrate reproduction, very little is known about their synthesis in the ovary. The zebrafish (Danio rerio) display capability to synthesize all three HUFA via pathways involving desaturation and elongation of two precursors, the linoleic acid (LA, C18:2n-6) and linolenic acid (LNA, C18:3n-3). As a prerequisite to gain full understanding on the importance and regulation of ovarian HUFA synthesis, we described here the mRNA expression pattern of two enzymes; desaturase (fadsd6) and elongase (elovl5), involved in HUFA biosynthesis pathway, in different zebrafish ovarian follicle stages. Concurrently, the fatty acid profile of each follicle stage was also analyzed.</p> <p>Methods</p> <p>mRNA levels of fadsd6 and elovl5 in different ovarian follicle stages were determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assays. For analysis of the ovarian follicular fatty acid composition, gas chromatography was used.</p> <p>Results</p> <p>Our results have shown that desaturase displayed significant upregulation in expression during the oocyte maturation stage. Expression of elongase was significantly highest in pre-vitellogenic follicles, followed by maturation stage. Fatty acid composition analysis of different ovarian follicle stages also showed that ARA level was significantly highest in pre-vitellogenic and matured follicles. DHA level was highest in both late vitellogenic and maturation stage.</p> <p>Conclusion</p> <p>Collectively, our findings seem to suggest the existence of a HUFA synthesis system, which could be responsible for the synthesis of HUFA to promote oocyte maturation and possibly ovulation processes. The many advantages of zebrafish as model system to understand folliculogenesis will be useful platform to further elucidate the regulatory and mechanism aspects of ovarian HUFA synthesis.</p>http://www.rbej.com/content/6/1/56
spellingShingle Enyu Yee-Ling
Jaya-Ram Annette
Khong Hou-Keat
Tan Sze-Huey
Ishak Sairatul D
Kuah Meng-Kiat
Shu-Chien Alexander
Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish
Reproductive Biology and Endocrinology
title Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish
title_full Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish
title_fullStr Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish
title_full_unstemmed Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish
title_short Upregulated mRNA expression of desaturase and elongase, two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish
title_sort upregulated mrna expression of desaturase and elongase two enzymes involved in highly unsaturated fatty acids biosynthesis pathways during follicle maturation in zebrafish
url http://www.rbej.com/content/6/1/56
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