Differential induction of four msx homeobox genes during fin development and regeneration in zebrafish.
Differential induction of four msx homeobox genes during fin development and regeneration in zebrafish.
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发表时间：
1995-02
期刊：
影响因子：
4.6
通讯作者：
M. Akimenko;Stephen L. Johnson;M. Westerfield;M. Ekker
中科院分区：
文献类型：
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作者：
M. Akimenko;Stephen L. Johnson;M. Westerfield;M. Ekker
为了研究斑马鱼鳍发育和再生过程中生长控制和模式形成的遗传调控，我们分析了4个同源盒基因msxA、msxB、msxC和msxD在斑马鱼鳍中的表达。在发育过程中，产生不成对鳍的中间鳍褶表达了这四个msx基因。这些基因的转录本也存在于假定的胸鳍芽的细胞中。除msxC基因外，最末端的细胞、成对鳍的顶端外胚层脊和中间鳍褶的间隙细胞和侧翼细胞均表达msx基因。位于最末端细胞下面的间充质细胞表达所有四种基因。msx基因在鳍褶和鳍芽中的表达是短暂的，在受精后3天，msx基因在中间鳍褶中的表达低于原位杂交检测的水平。虽然成年斑马鱼的鳍通常具有原位杂交检测不到的msx转录本水平，但在成对和未成对鳍的再生过程中，所有四个基因的表达都被强烈地重新诱导。在尾鳍再生中，msx基因表达的诱导最早发生在截肢后30小时。随着胚柄的形成，表达量增加，在第3 ~ 5天达到最大值。然后，msx的表达逐渐下降，并在第12天尾鳍恢复到正常大小时消失。在再生鳍中，每个鳍尖发育的胚母细胞表达msxB和msxC。上覆上皮细胞表达msxA和msxD，但不表达msxB或msxC。在鳍近远端轴的不同水平截肢表明msxB的表达取决于囊胚的位置，快速增殖的近端囊胚的细胞表达水平高于增殖较慢的远端囊胚的细胞。msxC和msxD的表达与胚母细胞沿该轴的位置无关。我们的研究结果表明，在鳍发育和再生过程中，四个msx基因中的每一个都有不同的作用，以及它们表达的差异调控。
To study the genetic regulation of growth control and pattern formation during fin development and regeneration, we have analysed the expression of four homeobox genes, msxA, msxB, msxC and msxD in zebrafish fins. The median fin fold, which gives rise to the unpaired fins, expresses these four msx genes during development. Transcripts of the genes are also present in cells of the presumptive pectoral fin buds. The most distal cells, the apical ectodermal ridge of the paired fins and the cleft and flanking cells of the median fin fold express all these msx genes with the exception of msxC. Mesenchymal cells underlying the most distal cells express all four genes. Expression of the msx genes in the fin fold and fin buds is transient and, by 3 days after fertilization, msx expression in the median fin fold falls below levels detectable by in situ hybridization. Although the fins of adult zebrafish normally have levels of msx transcripts undetectable by in situ hybridization, expression of all four genes is strongly reinduced during regeneration of both paired and unpaired fins. Induction of msx gene expression in regenerating caudal fins occurs as early as 30 hours postamputation. As the blastema forms, the levels of expression increase and reach a maximum between the third and fifth days. Then, msx expression progressively declines and disappears by day 12 when the caudal fin has grown back to its normal size. In the regenerating fin, the blastema cells that develop at the tip of each fin ray express msxB and msxC. Cells of the overlying epithelium express msxA and msxD, but do not express msxB or msxC. Amputations at various levels along the proximodistal axis of the fin suggest that msxB expression depends upon the position of the blastema, with cells of the rapidly proliferating proximal blastema expressing higher levels than the cells of the less rapidly proliferating distal blastema. Expression of msxC and msxD is independent of the position of the blastema cell along this axis. Our results suggest distinct roles for each of the four msx genes during fin development and regeneration and differential regulation of their expression.