Cloning of the growth hormone cDNA of alligator gar Atractosteus spatula and its expression through larval development.
The alligator gar (Atractosteus spatula) is the largest freshwater fish inhabiting rivers draining into the Gulf of Mexico. This primitive fish shows a fast growth rate since its early larval stages. This is attributed to the action of growth hormone (GH), an anterior pituitary gland hormone responsible for linear growth in vertebrates that can also be expressed in extrapituitary adult tissues and in fish embryos. The present research was aimed at obtaining the GH coding sequence of the alligator gar and studying its expression through larval development. A cDNA was obtained by RT-PCR, cloned and sequenced. The alligator gar GH cDNA sequence shares 98% nucleotide similarity with that reported for Lepisosteus osseus, indicating a very slow evolution of the GH within the primitive fish, in contrast with the burst of changes observed in euteleosts. Using RT-PCR and RNA nuclease protection assays, GH transcripts were detected at very high levels in eggs, embryos and in several larval stages. These data suggest that the GH may play an important role during embryogenesis in fish. The better understanding of alligator gar larval physiology will facilitate the culture of larvae and juvenile gar and consequently may allow the restoration of their natural populations.
Revol
Agnès
A
Departamento de Inmunología, Universidad Autónoma de Nuevo León, Facultad de Medicina, Av. Madero y Dr. A. Pequeño, Col. Mitras Centro, CP64460, Monterrey, México.
Garza Rodríguez
Maria de Lourdes
Mde L
Hernández Montenegro
Víctor
V
Aguilera
Carlos
C
Barrera Saldaña
Hugo
H
Mendoza
Roberto
R
D000489:Alligators and Crocodiles / Q000254:growth & development* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D013006:Growth Hormone / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D007814:Larva / Q000254:growth & development / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000235:genetics; D016415:Sequence Alignment; D014158:Transcription, Genetic / Q000235:genetics
D018076:DNA, Complementary; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D013006:Growth Hormone