Regulation of beta-tubulin function and expression in Drosophila spermatogenesis.
Regulation of beta-tubulin function and expression in Drosophila spermatogenesis.
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果蝇精子发生中β-微管蛋白功能和表达的调节。
DOI：
10.1002/dvg.1020160208
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Raff,EC
中科院分区：
文献类型：
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作者：
Hoyle,HD;Hutchens,JA;Turner,FR;Raff,EC
在这项研究中，我们研究了β-微管蛋白在果蝇精子发生中的两个方面的功能：1）β-微管蛋白的结构要求，用于组装不同类别的微管; 2）调节要求，用于产生正确的微管蛋白水平。在正常果蝇精子发生中，睾丸特异性β2-微管蛋白亚型支持多种微管功能。我们之前的工作表明，果蝇的另一种亚型β3不能支持精子发生，而β2的羧基截短形式β2ΔC至少在一定程度上可以提供β2的所有正常功能，除了一个：β2ΔC不能支持轴丝微管组织成轴丝的超分子结构。在这里，为了测试β2羧基序列是否可以挽救β3亚型在精子发生中的功能失效，我们构建了一个编码嵌合蛋白β3β2C的基因，其中羧基区域的β3序列被β2取代。与β3或β2ΔC不同，β3β2C可以为轴丝微管的组装及其组织成轴丝的超分子结构提供部分功能。特别地，β2羧基序列介导轴丝双重小管复合物的形态发生，包括辅助微管组装以及辐条和接头的附着。然而，我们的数据也揭示了β2特异性功能的一些方面，这些功能需要的结构特征不同于同种型定义可变区、C末端和内部可变区的一级序列。在共表达Δ2和嵌合Δ3Δ2C蛋白的雄性中进行的生殖力测试表明，在果蝇中，雄性和雌性生殖道中对精子活力的要求不同。由于精子发生中微管功能的某些方面对微管蛋白池的大小敏感，我们研究了雄性生殖细胞中微管蛋白水平的控制机制。我们发现Δ2-微管蛋白mRNA的积累和蛋白质的合成都依赖于基因剂量，并且表达水平受Δ2基因中3′端非编码序列的调节。我们的数据表明，调控机制，控制微管蛋白池水平的果蝇雄性生殖细胞不同于那些观察到的培养动物体细胞。最后，转基因构建体的表达与果蝇精子发生中×染色体表达的早期停止一致。© 1995 Wiley利斯公司
In this study we examined two aspects of β‐tubulin function inDrosophilaspermatogenesis: 1) β‐tubulin structural requirements for assembly of different categories of microtubules and 2) regulatory requirements for production of the correct tubulin protein level. In normalDrosophilaspermatogenesis, the testis‐specific β2‐tubulin isoform supports multiple microtubule functions. Our previous work showed that anotherDrosophilaisoform, β3, cannot support spermatogenesis, whereas a carboxyl‐truncated form of β2, β2ΔC, can at least to some extent provide all of β2′s normal functions, save one: β2ΔC cannot support organization of axonemal microtubules into the supramolecular architecture of the axoneme. Here, to test whether β2 carboxyl sequences can rescue the functional failure of the β3 isoform in spermatogenesis, we constructed a gene encoding a chimeric protein, β3β2C, in which β3 sequences in the carboxyl region are replaced with those of β2. Unlike either β3 or β2ΔC, β3β2C can provide partial function for both assembly of axonemal microtubules and their organization into the supramolecular architecture of the axoneme. In particular, the β2 carboxyl sequences mediate morphogenesis of the axoneme doublet tubule complex, including accessory microtubule assembly and attachment of spokes and linkers. However, our data also reveal aspects of β2‐specific function that require structural features other than the primary sequence of the isotype‐defining variable regions, the C terminus and the internal variable region. Tests of fecundity in males that co‐express Δ2 and the chimeric Δ3Δ2C protein showed that in Drosophila there are differential requirements for sperm motility in the male and in the female reproductive tract. Since some aspects of microtubule function in spermatogenesis are sensitive to the tubulin pool size, we examined the mechanisms for control of tubulin protein levels in the male germ cells. We found that both Δ2‐tubulin mRNA accumulation and protein synthesis are dependent on gene dose, and that the level of expression is regulated by 3′ noncoding sequences in the Δ2 gene. Our data show that the regulatory mechanisms that control tubulin pool levels in the Drosophila male germ line differ from those observed in cultured animal somatic cells. Finally, expression of transgenic constructs is consistent with early cessation of × chromosome expression inDrosophilaspermatogenesis. © 1995 Wiley‐Liss, Inc.