De Martino C, Capanna E, Nicotra M R, Natali P G
Cell Tissue Res. 1980;213(1):159-78. doi: 10.1007/BF00236928.
Smooth muscle heavy myosin and actin have been detected in mouse and rat meiotic chromosomes, by indirect immunofluorescence performed on testis cryostat sections and isolated germ cells. Both contractile proteins are detectable in the nuclei of meiotic cells during the first prophase. The appearance and disappearance time of myosin and actin, however, is not synchronous. While actin is visible in small spots from resting to late diplotene spermatocytes, myosin appears as filaments in the primary spermatocytes from the zygotene to the early state of diplotene. The number of myosin filaments in the pachytene spermatocytes corresponds to the number of bivalent chromosomes, whereas actin spots constantly outnumber the pairing chromosomes by two units. These immunochemical observations suggest that the two contractile proteins are associated with the synaptonemal complex (SC). Myosin seems to be associated with the central region of the SC, while actin is present in its basal knob which is in connection with the nuclear membrane. The difference in number between myosin filaments and actin spots appears to be related to the peculiar behaviour of the pairing sex chromosomes. The presence of contractile proteins in the nuclei of primary spermatocytes seems to suggest that they might play a role in the process of pairing of homologous chromosomes.
通过对睾丸冷冻切片和分离的生殖细胞进行间接免疫荧光检测，在小鼠和大鼠减数分裂染色体中检测到了平滑肌重肌球蛋白和肌动蛋白。在第一次减数分裂前期，这两种收缩蛋白在减数分裂细胞的细胞核中均可检测到。然而，肌球蛋白和肌动蛋白出现和消失的时间并不同步。从静止期到双线期晚期的精母细胞中，肌动蛋白以小点状可见，而从偶线期到双线期早期的初级精母细胞中，肌球蛋白则呈现为细丝状。粗线期精母细胞中肌球蛋白细丝的数量与二价染色体的数量相对应，而肌动蛋白小点的数量始终比配对染色体多两个单位。这些免疫化学观察结果表明，这两种收缩蛋白与联会复合体（SC）相关。肌球蛋白似乎与SC的中央区域相关，而肌动蛋白则存在于与核膜相连的基部节中。肌球蛋白细丝和肌动蛋白小点数量上的差异似乎与配对性染色体的特殊行为有关。初级精母细胞核中收缩蛋白的存在似乎表明它们可能在同源染色体配对过程中发挥作用。
