Atkinson B G, Raizada M, Bouchard R A, Frappier R H, Walden D B
Department of Zoology, University of Western Ontario, London, Canada.
Dev Genet. 1993;14(1):15-26. doi: 10.1002/dvg.1020140104.
The small (18-kDa) heat shock proteins (hsps) of maize are encoded by a complex multigene family. In a previous report, we described the genetic information from cDNAs encoding two different members of the family. In this communication, we report the isolation and characterization of cDNA and genomic clones encoding information for a third member of this hsp family (c/gMHSP18-1). DNA fragments containing nucleotide sequences common to, or specific for, each of these characterized 18-kDa genes were prepared and used as probes to assess the expression of these genes during microsporogenesis and development of the gametophyte in an inbred line of maize (Oh43). Our results demonstrate (1) that mRNA transcripts encoding the 18-kDa hsps are expressed and/or accumulate during microsporogenesis, and (2) that genes encoding two of the characterized 18-kDa hsps are expressed and/or accumulate independently, in a stage-specific manner during microsporogenesis. These observations imply that the stage-specific expression of particular 18-kDa hsp genes results from gene-specific regulation during microsporogenesis and gametophyte development rather than from an overall activation of the heat shock or stress response.
玉米的小（18千道尔顿）热休克蛋白（hsps）由一个复杂的多基因家族编码。在之前的一份报告中，我们描述了来自编码该家族两个不同成员的cDNA的遗传信息。在本通讯中，我们报告了编码该hsp家族第三个成员（c/gMHSP18-1）信息的cDNA和基因组克隆的分离与特性分析。制备了包含这些已鉴定的18千道尔顿基因中每个基因共有的或特有的核苷酸序列的DNA片段，并用作探针来评估这些基因在玉米自交系（Oh43）的小孢子发生和配子体发育过程中的表达。我们的结果表明：（1）编码18千道尔顿hsps的mRNA转录本在小孢子发生过程中表达和/或积累；（2）编码两个已鉴定的18千道尔顿hsps的基因在小孢子发生过程中以阶段特异性方式独立表达和/或积累。这些观察结果表明，特定18千道尔顿hsp基因的阶段特异性表达是由小孢子发生和配子体发育过程中的基因特异性调控引起的，而不是由热休克或应激反应的全面激活引起的。
