Barraclough R, Kimbell R, Rudland P S
J Cell Physiol. 1987 Jun;131(3):393-401. doi: 10.1002/jcp.1041310311.
Thy-1 antigen and laminin are two components often associated with the basement membrane of the rat mammary gland and are thought to be synthesized, at least in part, by the adjacent myoepithelial cells in vivo. The relative levels of Thy-1 mRNA and laminin mRNA are compared in a rat mammary cuboidal epithelial cell line and a derivative elongated myoepithelial-like cell line by hybridizing cloned cDNAs to cellular mRNA isolated from these cell types. Although the elongated myoepithelial-like cells synthesize four times as much laminin protein as the cuboidal epithelial cells, there is only a 1.7-fold increase in laminin mRNA between the two cell types. In contrast the 17-fold increase in Thy-1 antigen between the elongated cells and the cuboidal cells can be accounted for completely by a 14-18-fold increase in Thy-1 mRNA, suggesting that changes in the steady-state levels of Thy-1 mRNA in these cell lines are modulated at either a transcriptional or a post-transcriptional level. Run-off transcription by nuclei isolated from the cell lines does not distinguish between these two possibilities. The comparative results on Thy-1 antigen and laminin show that the enhanced production of two proteins often associated with the basement membrane of the rat mammary gland can be controlled at different levels in the elongated myoepithelial-like cells.
Thy-1抗原和层粘连蛋白是两种常与大鼠乳腺基底膜相关的成分，并且被认为至少部分是由体内相邻的肌上皮细胞合成的。通过将克隆的cDNA与从这些细胞类型中分离出的细胞mRNA杂交，比较了大鼠乳腺立方上皮细胞系和衍生的伸长的肌上皮样细胞系中Thy-1 mRNA和层粘连蛋白mRNA的相对水平。尽管伸长的肌上皮样细胞合成的层粘连蛋白蛋白是立方上皮细胞的四倍，但两种细胞类型之间的层粘连蛋白mRNA仅增加了1.7倍。相比之下，伸长细胞和立方细胞之间Thy-1抗原增加的17倍可以完全由Thy-1 mRNA增加的14 - 18倍来解释，这表明这些细胞系中Thy-1 mRNA稳态水平的变化在转录或转录后水平受到调节。从细胞系中分离的细胞核进行的连续转录无法区分这两种可能性。关于Thy-1抗原和层粘连蛋白的比较结果表明，在伸长的肌上皮样细胞中，两种常与大鼠乳腺基底膜相关的蛋白质的增强产生可以在不同水平受到控制。
