Slaughter G R, Meistrich M L, Means A R
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030.
Biol Reprod. 1989 Feb;40(2):395-405. doi: 10.1095/biolreprod40.2.395.
Messenger RNAs encoding calmodulin, alpha- and beta-tubulins, and actins were analyzed in nucleic acid isolated from purified rat testis cell populations. Cell-specific patterns were discovered that suggest coordinate regulation of members of different gene families. Genes that are candidates for coordinate regulation include those encoding 1.4 kb calmodulin RNA and 1.8 kb alpha-tubulin RNAs; 1.6 kb calmodulin RNA and a 1.8 kb beta-tubulin RNA; and 1.6 kb actin and 2.1 kb alpha-tubulin RNAs. The steady state level of the 2.2 kb actin RNA(s) varies less than any other RNA analyzed. Actin RNAs of approximately 1.6 kb are observed in fractions enriched for A spermatogonia or round spermatids or cytoplasts shed from elongating spermatids. The level of 1.8 kb alpha-tubulin RNA increases in a fraction enriched for leptotene-zygotene spermatocytes and peaks in pachytene spermatocytes. As the level of this alpha-tubulin RNA species decreases in maturing spermatids a new 2.1 kb alpha-tubulin RNA increases. beta-Tubulin RNAs of 2.7 and 1.8 kb are present in somatic and premeiotic cell fractions. beta-Tubulin RNA transcripts of 1.8 kb that increase in pachytene spermatocytes are derived from a different gene than that expressed in premeiotic cells. The major RNA that hybridizes to the chicken calmodulin cDNA is 1.4 kb; it increases during the development of spermatocytes, reaching a maximum level in pachytene spermatocytes before it declines during spermiogenesis. Calmodulin RNAs of 1.6 and 1.0 kb are clearly evident in the round spermatid fraction. These data reveal that mechanisms exist for cell-selective elevation of mRNAs encoding cytoskeletal proteins during rat spermatogenesis.
对从纯化的大鼠睾丸细胞群体中分离出的核酸进行分析，以检测编码钙调蛋白、α-和β-微管蛋白以及肌动蛋白的信使核糖核酸。发现了细胞特异性模式，这表明不同基因家族的成员受到协同调控。可能受到协同调控的基因包括那些编码1.4 kb钙调蛋白RNA和1.8 kbα-微管蛋白RNA的基因；1.6 kb钙调蛋白RNA和1.8 kbβ-微管蛋白RNA的基因；以及1.6 kb肌动蛋白和2.1 kbα-微管蛋白RNA的基因。2.2 kb肌动蛋白RNA的稳态水平变化小于所分析的任何其他RNA。在富含A型精原细胞、圆形精子细胞或伸长精子细胞脱落的细胞质的组分中观察到约1.6 kb的肌动蛋白RNA。1.8 kbα-微管蛋白RNA的水平在富含细线期-偶线期精母细胞的组分中升高，并在粗线期精母细胞中达到峰值。随着这种α-微管蛋白RNA种类在成熟精子细胞中的水平下降，一种新的2.1 kbα-微管蛋白RNA增加。2.7 kb和1.8 kb的β-微管蛋白RNA存在于体细胞和减数分裂前细胞组分中。在粗线期精母细胞中增加的1.8 kbβ-微管蛋白RNA转录本来自与减数分裂前细胞中表达的基因不同的基因。与鸡钙调蛋白cDNA杂交的主要RNA为1.4 kb；它在精母细胞发育过程中增加，在粗线期精母细胞中达到最高水平，然后在精子发生过程中下降。1.6 kb和1.0 kb的钙调蛋白RNA在圆形精子细胞组分中明显可见。这些数据表明，在大鼠精子发生过程中存在细胞选择性升高编码细胞骨架蛋白的mRNA的机制。
