Among growth hormone genes, those for prolactin gene and somatolactin gene
show the same number of expressed sites. While no homologues are observed for
expression site I, amino acid sequence homologues did appear for exon II to V, and
the discovery of a transcription regulation area in the upper region of exon I is
thought to indicate common ancestry.
Kawauchi et al. found that growth promotion effects actually did occur from
introduction of growth hormone genes into fish and abalone. Through inserting
these growth hormone genes into a fertilized egg, they were able to create a “super
salmon” that grew to large sizes in a short time. At Pukyong National University,
Kim et al. created a “super mud loach”.
C. Transferrin Genes
Transferrin has a molecular weight of around 75,000 and is a kind of b-globin. It is
an iron-carrying glycoprotein: two of molecules absorbed into serum bond with iron
ions (Fe
3+ ), supplying cells with the iron they need for proliferation and hemoglobin production by means of transferrin receptors. Over 99% of iron in serum
binds with transferrin. Normally, around one-third of transferrin binds with iron; the
remaining quantity that does not bind with iron is referred to as unsaturated iron
binding capacity (UIBC) (Liu et al. 2010).
Alongside insulin and selenious acid, transferrin is one of the three necessary
additives to the serum medium for animal cell cultures. It is also an important active
substance as an accelerator factor for scleromere differentiation. Transferrin and
similarly structured lactoferrin are involved in immune function regulation and
regulate cytokine secretion and the differentiation and proliferation of lymphocytes.
Administration to rainbow trout has been found to result in higher levels of
phagocytosis and chemiluminescence by means of macrophage and eosinophilic
leukocyte receptors.
Isozyme polymorphism analysis of coho salmon transferrin showed the existence
of three types (A, B, and C). Coho salmon possessing the C variety were found to be
strongly resistant to bacterial kidney disease (BKD) (Suzumoto et al. 1977). It
remains unknown whether transferrin acts directly on pathogenic bacteria, or whether there exists a gene with resistance to the BKD bacterium Renibacterium
salmoninarum in genomes of the C type. It is necessary, however, to create new fish
that are resistant to infection through the use of genetic engineering methods rather
than the traditional hybridization breeding and selection approach. By cloning and
analyzing transferrin genes in Japanese rice fish, salmon, flounder, and other fish,
Takashima discovered that the length of the protein open reading frame
(ORF) coding for transferrin proteins, though slightly different from one species to
the next, formed a sequence of 2061–2073 bp (687–691 amino acids). Structures for
this transferrin family are known to be similar in the front portion (N-lobe) and back
portion (C-lobe) of the peptide chain and to be created through gene duplication.
Japanese rice fish transferrin genes, like those in human beings, consist of 17
exon and 16 intron. The length of the exon is no different than in humans, but the
intron are characteristically very short. The amino acids needed for iron bonding
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3 Fish Genetics
show the same number of expressed sites. While no homologues are observed for
expression site I, amino acid sequence homologues did appear for exon II to V, and
the discovery of a transcription regulation area in the upper region of exon I is
thought to indicate common ancestry.
Kawauchi et al. found that growth promotion effects actually did occur from
introduction of growth hormone genes into fish and abalone. Through inserting
these growth hormone genes into a fertilized egg, they were able to create a “super
salmon” that grew to large sizes in a short time. At Pukyong National University,
Kim et al. created a “super mud loach”.
C. Transferrin Genes
Transferrin has a molecular weight of around 75,000 and is a kind of b-globin. It is
an iron-carrying glycoprotein: two of molecules absorbed into serum bond with iron
ions (Fe
3+ ), supplying cells with the iron they need for proliferation and hemoglobin production by means of transferrin receptors. Over 99% of iron in serum
binds with transferrin. Normally, around one-third of transferrin binds with iron; the
remaining quantity that does not bind with iron is referred to as unsaturated iron
binding capacity (UIBC) (Liu et al. 2010).
Alongside insulin and selenious acid, transferrin is one of the three necessary
additives to the serum medium for animal cell cultures. It is also an important active
substance as an accelerator factor for scleromere differentiation. Transferrin and
similarly structured lactoferrin are involved in immune function regulation and
regulate cytokine secretion and the differentiation and proliferation of lymphocytes.
Administration to rainbow trout has been found to result in higher levels of
phagocytosis and chemiluminescence by means of macrophage and eosinophilic
leukocyte receptors.
Isozyme polymorphism analysis of coho salmon transferrin showed the existence
of three types (A, B, and C). Coho salmon possessing the C variety were found to be
strongly resistant to bacterial kidney disease (BKD) (Suzumoto et al. 1977). It
remains unknown whether transferrin acts directly on pathogenic bacteria, or whether there exists a gene with resistance to the BKD bacterium Renibacterium
salmoninarum in genomes of the C type. It is necessary, however, to create new fish
that are resistant to infection through the use of genetic engineering methods rather
than the traditional hybridization breeding and selection approach. By cloning and
analyzing transferrin genes in Japanese rice fish, salmon, flounder, and other fish,
Takashima discovered that the length of the protein open reading frame
(ORF) coding for transferrin proteins, though slightly different from one species to
the next, formed a sequence of 2061–2073 bp (687–691 amino acids). Structures for
this transferrin family are known to be similar in the front portion (N-lobe) and back
portion (C-lobe) of the peptide chain and to be created through gene duplication.
Japanese rice fish transferrin genes, like those in human beings, consist of 17
exon and 16 intron. The length of the exon is no different than in humans, but the
intron are characteristically very short. The amino acids needed for iron bonding
70
3 Fish Genetics