Expression and inheritance of RSVLTR-rtGH1 complementary DNA in the transgenic common carp, Cyprinus carpio.

Transgenic common carp, Cyprinus carpio, possessing the long terminal repeat (LTR) sequence of avian Rous sarcoma virus (RSV) fused to the rainbow trout (rt) growth hormone (GH1) complementary DNA (cDNA) were produced by microinjection. Initial studies showed that the transgenic common carp transmitted the foreign DNA to a significant fraction of their progeny in three of four crosses of transgenic males with control females. These progeny grew 20 to 40% faster than their nontransgenic full siblings. In this study, additional experiments were conducted to evaluate inheritance and expression of the foreign GH gene in transgenic common carp, and the growth performance of these transgenic fish. Four P1 (parental generation produced by microinjection) x nontransgenic controls, four P1 x P1, and one P1 x F1 matings of transgenic carp containing RSVLTR-rtGH1 cDNA were made. The percentages of transgenic progeny resulting from these matings were: 0, 32, 42, 100 (4 progeny only), 21, 21, 31, 30, and 23%, respectively. All crosses except 1 siblot (control x P1) exhibited progeny ratios below the expected 50 or 75% transgenic. These results indicate that most of these transgenic P1 had the foreign gene in their germ line but were mosaics, and at least one transgenic individual did not have the RSVLTR-rtGH1 cDNA in the gonadal tissue. Both P1 and F1 transgenic fish produce trout growth hormone mRNA and polypeptide as determined by reverse transcription polymerase chain reaction amplification, RNA dot-blot hybridization, and radio-immunobinding assay. Growth response by families of F1 transgenic fish to the addition of rtGH1 cDNA varied widely.(ABSTRACT TRUNCATED AT 250 WORDS)

Transfer, expression, and inheritance of salmonid growth hormone genes in channel catfish, Ictalurus punctatus, and effects on performance traits.

We examined expression and inheritance of salmonid growth hormone genes RSVLTR-rtGH1 cDNA and RSVLTR-csGH cDNA, transferred to channel catfish (Ictalurus punctatus) by microinjection. One to 9 copies of the foreign DNA were inserted in either head-to-tail tandem array at single insertion sites or single copies at multiple insertion sites. All P1 transgenic catfish evaluated produced salmonid growth hormone regardless of the construct. Five P1 x P1 matings were accomplished. The spawning rate and fertility of these P1 transgenics in artificial spawning conditions were comparable to those of normal channel catfish. In two of three years, 100% spawning and 100% hatch were obtained. Percent transgenic progeny observed in the five matings were 20, 52, 7, 47, and 0%, which was lower (P < 0.001, chi 2) than the 75% inheritance expected assuming the P1 brood stock had at least one copy of the foreign gene integrated and were not mosaics in the germ line. At least 7 of 10 P1 were mosaics, and a minimum of 2 of 10 P1 did not possess the salmonid growth hormone genes in their germ line. P1 transgenics grew at the same rate as their nontransgenic full siblings, which is not surprising because the P1 were mosaics. F1 transgenic progeny in two families possessing RSVLTR-csGH cDNA grew 26% faster, to 40 to 50 gm, than their nontransgenic full siblings when evaluated communally. One F1 progeny group produced by RSVLTR-rtGH1 cDNA x RSVLTR-csGH cDNA mating and one F1 progeny group (parents either RSVLTR-rtGH1 cDNA or RSVLTR-csGH cDNA) grew at the same rate as normal full siblings when grown communally to 25 gm and 60 mg, respectively. In families where F1 progeny grew faster than controls, the range in body weight and coefficient of variation for the transgenic full siblings were less than those for controls. In families where F1 progeny grew at the same rate as controls, range in body weight and coefficient of variation were similar for transgenic and normal individuals. The percent deformities observed in P1 transgenics (13.6%) was higher (P < 0.05) than in microinjected P1 nontransgenics (5.1%). Percent deformities in transgenics and control F1 channel catfish was not different (p > 0.05; 0.5 and 2.8%, respectively).