Differentiation in Volvox carteri: Study of Pattern Variation of Reproductive Cells
Differentiation in Volvox carteri: Study of Pattern Variation of Reproductive Cells
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团藻的分化：生殖细胞模式变异的研究
DOI：
10.1515/znc-1982-1024
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发表时间：
1982
期刊：
影响因子：
--
通讯作者：
L. Jaenicke
中科院分区：
文献类型：
--
作者：
R. Gilles;L. Jaenicke
摘要多细胞绿色团藻的无性生殖球体由两种细胞组成：无鞭毛生殖它们是由胚胎发生过程中的分化卵裂所决定的。成体球状体的分生孢子形成一个对称的图案，由四层组成，每层四个分生孢子;它们的位置已经在胚胎中由分生孢子的原始细胞确定。一般认为，16个分生孢子的模式是基本模式，但大多数球状体的分生孢子较少（最少为8个）。9种可能的生殖器模式（8至16个生殖器）的描述和相关的生殖器干细胞已分化。分生孢子模式的缺陷特别令人感兴趣，因为任何分化模型不仅要解释形成的基本模式，还要解释其系统变异。我们的研究表明，模式减少绝不是随机的，而是由一个内在的机制，将第一个不平等的分裂从32细胞阶段转移到16细胞阶段。所有形成的模式都可以从涉及干细胞的非同步分化的裂解途径推断出来。因此，图案形成可以与胚胎发生期间调节事件的时间和间隔信号相关。
Abstract Asexual spheroids of the multicellular green alga Volvox are composed of two types o f cells: non-flagellated reproductive gonidia and Chlamydomonas-like flagellated somatic cells. They are committed by a differentiating cleavage during embryogenesis. The gonidia of the adult spheroids form a symmetrical pattern consisting of four layers of four gonidia each; their position is established already in the embryos by the gonidial initials. Whereas, generally, the 16-gonidia pattern is assumed to be the basic one, most o f the spheroids have fewer gonidia (down to 8). The nine possible gonidial patterns (8 to 16 gonidia) are described and correlated to the gonidial stem cells which have been differentiated. Defects in gonidial pattern are of particular interest, since any model of differentiation has to explain not only the basic pattern formed, but also its systematic variations. Our study shows that the pattern reduction is by no means random, but governed by an intrinsic mechanism which shifts the first unequal cleavage from the 32-celled stage to the 16-celled stage. All the patterns formed can be deduced from cleavage pathways involving non-synchronous differentiation of the stem cells. Thus, pattern formation can be correlated to timing and spacing signals regulating events during embryogenesis.