Identification of cell-type-specific genes of Volvox carteri and characterization of their expression during the asexual life cycle.
Identification of cell-type-specific genes of Volvox carteri and characterization of their expression during the asexual life cycle.
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DOI：
10.1016/0012-1606(91)90212-l
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发表时间：
1991-05
影响因子：
2.7
通讯作者：
L. Tam;D. Kirk
中科院分区：
文献类型：
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作者：
L. Tam;D. Kirk
团藻具有两种形态和功能不同的细胞类型：体细胞和性腺（无性生殖细胞）。为了确定这两种细胞类型分化所涉及的发育程序，我们分离了31个非同源cDNA克隆，这些克隆与rna杂交，其中一种细胞类型比另一种细胞类型丰富得多。这些cdna检测到的转录本的细胞类型和阶段特异性表达的细节（加上先前由其他基因表征的五个基因）通过Northern-blot分析进行了检查。19个性腺转录本的积累模式可分为两类：其中一个基因的转录本在卵裂早期最丰富，而另外18个基因的转录本在性腺发育后期才达到最大丰度。同样，12个体细胞特异性转录本分为两类：5个“早期”体细胞基因的转录本在胚胎发育完成后不久就大量存在，而7个“晚期”体细胞基因的转录本直到发育后期才被检测到。另外3个基因的表达（两个参与鞭毛发育，一个编码细胞外基质成分）也被发现主要局限于体细胞。这些研究表明体细胞和性腺之间的表型差异至少可以部分解释为RNA积累的差异调节，并且在每种细胞类型中似乎存在多种细胞类型特异性转录物的积累模式。
Volvox carteripossesses two morphologically and functionally distinct cell types: somatic cells and gonidia (asexual reproductive cells). To define the developmental programs involved in the differentiation of these two cell types, we have isolated 31 nonhomologous cDNA clones that hybridized to RNAs that were significantly more abundant in one cell type than the other. Details of the cell-type- and stage-specificity of expression of the transcripts detected by these cDNAs (plus five genes previously characterized by others) were examined by Northern-blot analysis. Accumulation patterns for the 19 gonidial transcripts fell into two distinct classes: transcripts of one gene were maximally abundant in very early cleavage, whereas transcripts of the other 18 did not reach maximal abundance until quite late in gonidial development. Similarly, the 12 somatic-cell-specific transcripts fell into two categories: transcripts of 5 “early” somatic genes became abundant soon after the completion of embryogenesis, whereas transcripts of 7 “late” somatic genes were not detected until later developmental stages. Expression of 3 other genes (two involved in flagellar development and one that encodes an extracellular matrix component) was also found to be restricted largely to somatic cells. These studies indicate that phenotypic differences between somatic cells and gonidia can be at least partially explained by differential regulation of RNA accumulation, and that there appear to be multiple patterns of accumulation of cell-type-specific transcripts within each cell type.