A COILED-COIL RELATED PROTEIN-SPECIFIC FOR SYNAPSED REGIONS OF MEIOTIC PROPHASE CHROMOSOMES
A COILED-COIL RELATED PROTEIN-SPECIFIC FOR SYNAPSED REGIONS OF MEIOTIC PROPHASE CHROMOSOMES
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DOI：
10.1002/j.1460-2075.1992.tb05616.x
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发表时间：
1992-12-01
期刊：
影响因子：
11.4
通讯作者：
HEYTING, C
中科院分区：
文献类型：
--
作者：
MEUWISSEN, RLJ;OFFENBERG, HH;HEYTING, C
联会复合体是减数分裂前期同源染色体之间形成的结构。它们可能参与染色体配对和重组。使用单克隆抗SC抗体，我们分离的cDNA编码的主要组成部分的SC，这是本地化特异性的突触节的减数分裂前期染色体。从全长cDNA的核苷酸序列预测的蛋白质，命名为SCP 1，由946个氨基酸残基组成，分子量为111 kDa。它与核纤层蛋白和一些最近鉴定的核基质蛋白有几个共同特征。SCP 1的主要部分由能够形成两亲性α-螺旋的长片段组成。该区域显示与肌球蛋白重链的卷曲螺旋区的氨基酸序列相似性。亮氨酸拉链包括在该区域中。羧基端有两个小的碱性结构域和几个S/T-P-X-X基序，这是DNA结合蛋白的特征。这些基序之一是p34 cdc 2蛋白激酶的潜在靶位点。氨基端是酸性的，相对富含脯氨酸，但不含S/T-P-X-X基序。编码SCP 1基因的转录仅限于合子期-双线期精母细胞。针对cDNA克隆之一的融合蛋白产生的多克隆抗血清识别分离的SC的Western印迹上的单一蛋白，其电泳迁移率与由原始单克隆抗体（mAb）IX 5 B2识别的抗原的电泳迁移率相同。通过比较单克隆抗体IX 5 B2和多克隆抗融合蛋白抗血清对大鼠干细胞的免疫金标记，初步推断SCP 1的羧基端朝向外侧元件，而蛋白质的其他结构域则向外侧元件之间的中心区域延伸。我们的结论是，SCP 1是SC的横丝的主要组成部分，并推测它已经进化的核基质蛋白的专业化。
Synaptonemal complexes (SCs) are structures that are formed between homologous chromosomes during meiotic prophase. They are probably involved in chromosome pairing and recombination. Using a monoclonal anti-SC antibody we isolated cDNAs encoding a major component of SCs which is localized specifically in synapsed segments of meiotic prophase chromosomes. The protein predicted from the nucleotide sequence of a full-length cDNA, named SCP1, consists of 946 amino acid residues and has a molecular weight of 111 kDa. It shares several features with nuclear lamins and some recently identified nuclear matrix proteins. The major part of SCP1 consists of long stretches capable of forming amphipathic alpha-helices. This region shows amino acid sequence similarity to the coiled-coil region of myosin heavy chain. A leucine zipper is included in this region. The carboxy-terminus has two small basic domains and several S/T-P-X-X motifs, which are characteristic of DNA-binding proteins. One of these motifs is a potential target site for p34cdc2 protein kinase. The amino-terminus is acidic and relatively proline-rich, but does not contain the S/T-P-X-X motif. The transcription of the gene encoding SCP1 is restricted to zygotene-diplotene spermatocytes. A polyclonal antiserum raised against the fusion protein of one of the cDNA clones recognizes a single protein on Western blots of isolated SCs, with an electrophoretic mobility identical to that of the antigen recognized by the original monoclonal antibody (mAb), IX5B2. From a detailed comparison of the immunogold labelling of rat SCs by mAb IX5B2 and the polyclonal anti-fusion protein antiserum respectively, we tentatively infer that the carboxy-terminus of SCP1 is orientated towards the lateral elements and that the other domains of the protein extend towards the central region between the lateral elements. We conclude that SCP1 is the major component of the transverse filaments of SCs, and speculate that it has evolved by specialization of a nuclear matrix protein.