Homologies between members of the germin gene family in hexaploid wheat and similarities between these wheat germins and certain Physarum spherulins.
Homologies between members of the germin gene family in hexaploid wheat and similarities between these wheat germins and certain Physarum spherulins.
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DOI：
10.1016/s0021-9258(18)99247-1
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发表时间：
1991-06
期刊：
影响因子：
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通讯作者：
B. Lane;F. Bernier;E. Dratewka-Kos;R. Shafai;T. Kennedy;C. Pyne;J. Munro;T. Vaughan;D. Walters;F. Altomare
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文献类型：
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作者：
B. Lane;F. Bernier;E. Dratewka-Kos;R. Shafai;T. Kennedy;C. Pyne;J. Munro;T. Vaughan;D. Walters;F. Altomare
通过使用“全长”胚芽蛋白 cDNA 探针筛选小麦 DNA 文库中大约 10(6) 个噬菌斑，检测到两个基因组克隆。当用 EcoRI 消化时，一个克隆产生了 2.8 千碱基对片段 (gf-2.8)，另一个克隆产生了 3.8 千碱基对片段 (gf-3.8)。通过核苷酸测序，发现gf-2.8和gf-3.8各自编码germin和germin mRNA的完整序列，并且含有大量的5'-和3'-侧翼序列。通过引物延伸确定gf-2.8中的“cap”位点，并以此类推推导出gf-3.8中的相应位点。 gf-2.8 和 gf-3.8 中的 mRNA 编码序列无内含子，并且彼此有 87% 同源性。 gf-2.8 和 gf-3.8 中的 5' 侧翼区域包含可能是顺式作用元件的可识别位点，但它们之间几乎没有任何显着相似性。除了 gf-2.8 和 gf-3.8 5' 侧翼区域中推定的 TATA 和 CAAT 盒外，gf-2.8 中还有富含 AT 的反向重复序列、GC 盒、长的富含嘌呤的序列、两个 19 碱基对的直接重复序列，以及一个非常长（200 碱基对）的反向重复序列（大约 90% 同源性）在GF-3.8中。 gf-2.8 和 gf-3.8 中成熟蛋白编码区之间 8% 的差异反映在相应 201 个残基蛋白之间相应 7% 的差异上。最显着的是，gf-2.8和gf-3.8中成熟蛋白编码区之间相同的8%差异与所编码的多肽序列的中心部分(61-151)没有任何变化有关。芽蛋白中的这个中心的、高度保守的核心似乎在蛋白质的生化参与中具有首要的重要性。当假定相似氨基酸之间具有等价性时，gf-2.8 和 gf-3.8 萌芽蛋白与多头绒泡菌的球蛋白 1a 和 1b 表现出显着的相似性（约 44%），这种相似性在萌芽蛋白的保守核心中增加到约 50%。靠近胚芽蛋白保守核心的中间 (87-96) 是一个罕见的 PH(I/T)HPRATEI 十肽序列，球蛋白（1a 和 1b）和胚芽蛋白（gf-2.8 和 gf-3.8）共有该序列。这些相似之处是在证据的背景下讨论的，这些证据可以解释为表明胚芽蛋白和球蛋白的生物化学与细胞（也许是细胞壁）对干燥、水合作用和渗透压的反应有关。（摘要截断为 400 字）
By screening approximately 10(6) plaques in a wheat DNA library with a “full-length” germin cDNA probe, two genomic clones were detected. When digested with EcoRI, one clone yielded a 2.8-kilobase pair fragment (gf-2.8) and the other yielded a 3.8-kilobase pair fragment (gf-3.8). By nucleotide sequencing, each of gf-2.8 and gf-3.8 was found to encode a complete sequence for germin and germin mRNA, and to contain appreciable amounts of 5'- and 3'-flanking sequences. The “cap” site in gf-2.8 was determined by primer extension and the corresponding site in gf-3.8 was deduced by analogy. The mRNA coding sequences in gf-2.8 and gf-3.8 are intronless and 87% homologous with one another. The 5'-flanking regions in gf-2.8 and gf-3.8 contain recognizable sites of what are probably cis-acting elements but there is otherwise little if any significant similarity between them. In addition to putative TATA and CAAT boxes in the 5'-flanking regions of gf-2.8 and gf-3.8, there are AT-rich inverted-repeats, GC boxes, long purine-rich sequences, two 19-base pair direct-repeat sequences in gf-2.8, and a remarkably long (200-base pair) inverted-repeat sequence (approximately 90% homology) in gf-3.8. An 8% difference between the mature-protein coding regions in gf-2.8 and gf-3.8 is reflected by a corresponding 7% difference between the corresponding 201-residue proteins. Most significantly, the same 8% difference between the mature-protein coding regions in gf-2.8 and gf-3.8 is allied with no change whatever in a central part (61-151) of the encoded polypeptide sequences. It seems likely that this central, strongly conserved core in the germins is of first importance in the biochemical involvements of the proteins. When an equivalence is assumed between like amino acids, the gf-2.8 and gf-3.8 germins show significant (approximately 44%) similarity to spherulins 1a and 1b of Physarum polycephalum, a similarity that increases to approximately 50% in the conserved core of germin. Near the middle (87-96) of the conserved core in the germins is a rare PH(I/T)HPRATEI decapeptide sequence which is shared by spherulins (1a and 1b) and germins (gf-2.8 and gf-3.8). These similarities are discussed in the context of evidence which can be interpreted to suggest that the biochemistry of germins and spherulins is involved with cellular, perhaps cell-wall responses to desiccation, hydration, and osmotic stress.(ABSTRACT TRUNCATED AT 400 WORDS)