Zou J, Cunningham C, Secombes C J
Department of Zoology, University of Aberdeen, UK.
Eur J Biochem. 1999 Feb;259(3):901-8. doi: 10.1046/j.1432-1327.1999.00121.x.
The rainbow trout interleukin (IL)-1 beta gene consists of six exons/five introns, in contrast to mammals which have seven exons/six introns. The missing exon appears to be at the 5' end of the gene, probably equivalent to exon 1 or 2 of mammals. Fewer and smaller introns make the trout IL-1 beta only half the size of mammalian IL-1 beta genes. Highest homology (> 60% amino acid similarity) is seen between exon 5 of trout and exon 6 of mammals. Reverse transcription-PCR analysis revealed two additional incompletely spliced variants of the trout IL-1 beta gene, containing intron 5 or introns 4 and 5. All three transcripts are detectable in gill, kidney, liver and spleen tissue from bacterially challenged fish but only the fully spliced transcript is detectable in blood. Northern blot analysis revealed that the latter transcript is also induced following stimulation of kidney leucocytes with lipopolysaccharide for 4 h. A second inducible transcript is also detected but is larger (approximately 3 kb) than any of the above, suggesting that it could be from a second gene. Southern blot analysis also suggests at least two copies of the IL-1 beta gene or genes related to the 3' end of the IL-1 beta sequence, are present in trout.
虹鳟鱼白细胞介素（IL）-1β基因由六个外显子/五个内含子组成，这与具有七个外显子/六个内含子的哺乳动物不同。缺失的外显子似乎位于该基因的5'端，可能相当于哺乳动物的外显子1或2。更少且更小的内含子使得鳟鱼IL-1β基因的大小仅为哺乳动物IL-1β基因的一半。在鳟鱼的外显子5和哺乳动物的外显子6之间观察到最高的同源性（氨基酸相似性>60%）。逆转录-聚合酶链反应分析揭示了鳟鱼IL-1β基因的另外两种不完全剪接变体，包含内含子5或内含子4和5。在受到细菌攻击的鱼的鳃、肾、肝和脾组织中可检测到所有三种转录本，但仅在血液中可检测到完全剪接的转录本。Northern印迹分析表明，在用脂多糖刺激肾白细胞4小时后，也可诱导产生后一种转录本。还检测到了第二种可诱导转录本，但其比上述任何一种转录本都大（约3 kb），这表明它可能来自第二个基因。Southern印迹分析还表明，在鳟鱼中存在至少两个与IL-1β序列3'端相关的IL-1β基因拷贝。
