博士 / 國立臺灣大學 / 動物學研究所 / 91 / Abstract
The reproductive functions and mechanisms regulating vitellogenesis in crustaceas have been the subjects of controversy. We have cloned another type of vitellogenin cDNA (Vg1) another than Vg2 being described previously in freshwater giant prawn, Macrobrachium rosenbergii, and proven that Vg1 and Vg2 are simultaneously expressed. The similarity of the freshwater giant prawn Vg1 and Vg2 is as high as 94%, but the partial sequence of Vg1 fragment with 19 aa differs from that in Vg2. There are five amino acids are different and one is lost within the signal peptide of Vg2 N-terminal sequence compare to Vg1. The sequenced cDNA of Vg1 consisted of 7,800 bp, contains a 2,538 aa open reading frame which shows similarity to vitellogenin sequenes from other crustaceans. The intron location in the sequenced region of genomic DNA was also found similar among M. rosenbergii, Penaeus monodon, Litopenaeus vannamei and Metapenaeus ensis. Its deduced amino acid sequence possessed three consensus cleavage sites, RXRR, similar to those reported in Vgs of insects. The freshwater giant prawn Vg1 has six potential N-glycosylation sites, five of which were obtained in VnA and one in VnC. Sixteen residues of Cysteine having the potential for the disulphide bound formation within VnA, are existed in Vg1 and conserved well in vitellogenins from other crustaceans. Three histidine cluster motifs (HXXXXH, HXXXH and HXXHH) that are essential for catalysis of stearoyl-CoA desaturase activity were found in the deduced amino acid sequence of Vg1.
Two cDNAs encoding vitellogenin partial sequence were further cloned in the black tiger shrimp, P. monodon and American white shrimp, L. vannamei, and we found that the hepatopancreas is the main site of vitellogenin synthesis in these shrimps and freshwater giant prawn, while ovary is also the site of Vg synthesis in L. vannamei. Furthermore, the Vg1 and Vg2 of Macrobrachium rosenbergii can be expressed simultaneously in hepatopancreas and ovary. The Vg1 can be expression in juvenile Macrobrachium rosenbergii both sex by the stimulating of biogenic amines (serotonin, epinephrine and noreoinephrine).
| Identifer | oai:union.ndltd.org:TW/091NTU00312032 |
| Date | January 2003 |
| Creators | Deng-Yu Tseng, 曾登裕 |
| Contributors | Ching-Ming Kuo, Guang-Hsiung Kou, 郭欽明, 郭光雄 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 137 |
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