蓝太阳鱼生长激素全长cDNA的克隆与序列分析

The full length cDNA encoding growth hormone of a freshwater fish, Lepomis cyanellus, (LcGH) was cloned from pituitary RNA with RT-PCR, 3‘ and 5‘ RACE (rapid amplification of cDNA ends). The LcGH cDNA (Genbank No. AY530822), about 989nt (nucleotide) long, consisted of a open reading frame with 615nt long, 5‘and 3‘untranslated regions with 93nt and 224nt long respectively, and a 57nt poly (A) tail. The DNA sequence analysis showed that there are typical Kozak sequence and polyadenylation signal. The pregrowth hormone peptide of 204aa deduced from LcGH cDNA included a putative signal peptide (17aa) locating in its Nterminal. There exist a Asn-Cys-Thr glycosylation site at amino acid 201, and 4 cysteine residues (No. 69, 177, 194, 202) that are essential to construct two S-S bonds in this pregrowth hormone peptide. Homological comparision among LcGH and other species growth hormones showed that There is high homology (more than 85%) between growth hormone of Lepomis cyanellus and that of most perciformes fish, but low homology (less than 70%) in comparison with other species such as Siluriformes and Cypriniformes fish.     

蓝太阳鱼胚胎和仔鱼发育的观察

蓝太阳鱼成熟卵为粘性卵,卵中央具有一油球,卵子直径平均为0.75±0.05mm。在25±1℃的水温下,受精后45min开始第1次卵裂,从受精到脱膜的孵化时间大约为30h,脱膜后4d左右开始摄食。