Discontinuities and overlaps in patterning within single cells.
Discontinuities and overlaps in patterning within single cells.
复制标题
单细胞内图案的不连续性和重叠。
DOI：
10.1098/rstb.1981.0158
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
Nelsen,EM
中科院分区：
文献类型：
--
作者：
Frankel,J;Nelsen,EM
这类纤毛虫是纵向营养生长和周期性赤道细分的。有证据表明，这种细分涉及与裂变带相关的不连续的形成，这与多细胞生物中片段边界的表达非常相似。与纬度不同，细胞经度可以潜在地保持克隆的连续性。野生型细胞的收缩液泡孔（c.v.ps）纵向定位系统的特征表明，它是一个围绕细胞周长的圆形定位系统，参考边界与口腔发育轴一致。这个边界标志着一个不连续性，不像裂变区，它可以无性繁殖。一个隐性突变，janus(jan)，带来了c.v.p.定位的改变，这表明第二个纵向参考边界位于细胞周长的45%左右，在第一个细胞的右边。沿着第二边界，偶尔会出现异常的口腔结构，似乎维持着一个与主要系统相反方向的位置系统。当jan1首次在先前为jan1 +的细胞中表达时，c.v.p.经度模式逐渐从野生型细胞的特征转变为jan1模式；这种变化在沿第二参照边界出现异常口腔结构之前就开始了。我们认为这两个参考边界和它们控制的位置系统可能存在于野生型和詹细胞中。相反方向的位置系统很可能重叠。提出了一个简单的模型来说明重叠的位置系统如何协同产生所观察到的模式。
Ciliates such asTetrahymenamanifest longitudinal vegetative growth and periodic equatorial subdivision. Evidence is presented suggesting that this subdivision involves the formation of discontinuities associated with the fission zone that closely resemble expressions of the segment border in multicellular organisms. Unlike latitudes, cellular longitudes can potentially maintain clonal continuity. Features of the system of longitudinal positioning of contractile vacuole pores (c.v.ps) in wild-type cells are suggestive of a circular positional system wrapped around the cell circumference, with a reference border coinciding with the axis of oral development. This border marks a discontinuity that, unlike the fission zone, can be clonally propagated. A recessive mutant,janus( jan), brings about alterations in c.v.p. positioning that suggest that a second longitudinal reference border is located about 45 % of the cell circumference to the cell’s right of the first. This second border, along which abnormal oral structures sporadically appear, seems to maintain a positional system oriented in a direction opposite to the primary system. Whenjanfirst comes to expression in cells previouslyjan+, the pattern of c.v.p. longitudes changes gradually from that characteristic of wild-type cells to thejanpattern; this change begins before abnormal oral structures first appear along the second reference border. We suggest that the two reference borders, and the positional systems that they control, might be present in wild-type as well asjancells. The oppositely directed positional systems are likely to overlap. A simple model is proposed to illustrate how overlapping positional systems might cooperate to generate patterns such as those observed.