Juxtaposition of C(2)M and the transverse filament protein C(3)G within the central region of Drosophila synaptonemal complex
Juxtaposition of C(2)M and the transverse filament protein C(3)G within the central region of Drosophila synaptonemal complex
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DOI：
10.1073/pnas.0500172102
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发表时间：
2005-03-22
影响因子：
11.1
通讯作者：
Hawley, RS
中科院分区：
文献类型：
--
作者：
Anderson, LK;Royer, SM;Hawley, RS
联会复合体（SC）与大多数生物的减数分裂重组过程密切相关，但它的确切作用仍然是个谜。这种不确定性的一个原因是SC的整体结构在进化上是保守的，但许多SC蛋白不是。在果蝇中已经鉴定出两种推定的SC蛋白：C（3）G和C（2）M。任何一个基因的突变都会导致SC结构和减数分裂重组的缺陷。虽然这两个基因在氨基酸水平上都没有很好的保守性，但预测的C（3）G的二级结构与横丝蛋白的二级结构相似，C（2）M是α-Kleisin家族的远亲成员，该家族包括Rec 8，一种减数分裂特异性粘附蛋白。在这里，我们使用免疫金标记的果蝇卵巢SC定位C（3）G和C（2）M在EM水平。我们发现C（3）G和C（2）M都是SC的组成部分，C（3）G在SC中的取向与其他横丝蛋白相似，C（2）M的N端位于SC的中心区域，与横向元件（LE）相邻。基于我们的数据和已知的C（2）M和C（3）G突变体的表型，我们提出了一个SC结构模型，其中C（2）M连接C（3）G到LE。
The synaptonemal complex (SC) is intimately involved in the process of meiotic recombination in most organisms, but its exact role remains enigmatic. One reason for this uncertainty is that the overall structure of the SC is evolutionarily conserved, but many SC proteins are not. Two putative SC proteins have been identified in Drosophila: C(3)G and C(2)M. Mutations in either gene cause defects in SC structure and meiotic recombination. Although neither gene is well conserved at the amino acid level, the predicted secondary structure of C(3)G is similar to that of transverse-filament proteins, and C(2)M is a distantly related member of the alpha-kleisin family that includes Rec8, a meiosis-specific cohesin protein. Here, we use immunogold labeling of SCs in Drosophila ovaries to localize C(3)G and C(2)M at the EM level. We show that both C(3)G and C(2)M are components of the SC, that the orientation of C(3)G within the SC is similar to other transverse-filament proteins, and that the N terminus of C(2)M is located in the central region adjacent to the lateral elements (LEs). Based on our data and the known phenotypes of C(2)M and C(3)G mutants, we propose a model of SC structure in which C(2)M links C(3)G to the LEs.