Kurtz A, Vogel F, Funa K, Heldin C H, Grosse R
Department of Cellular Biochemistry, Academy of Science of the German Democratic Republic, Berlin-Buch.
J Cell Biol. 1990 May;110(5):1779-89. doi: 10.1083/jcb.110.5.1779.
The cDNA for a previously described growth inhibitor, designated as mammary-derived growth inhibitor (MDGI) (Grosse, R., and P. Langen. 1989. In Handbook of Experimental Pharmacology. In press) has been cloned from a plasmid library which was derived from terminally differentiated bovine mammary gland. Sequencing of the cDNA showed an open reading frame coding for a protein of 133 amino acids. In six positions differences were found between the sequence determined from the cDNA and that determined previously by amino acid sequence analysis. Northern blot analysis revealed abundant MDGI mRNA in the terminally differentiated mammary gland, whereas in virgin gland, liver or pancreas transcripts were not expressed. By use of in situ hybridization technique transcription of MDGI in the developing bovine mammary gland was analyzed. Increasing amounts of MDGI mRNA were detected in the epithelial cells of embryonic mammary rudiment, in the epithelium of developing lobules and in terminal parts of ducts and lobuloalveolar epithelial cells of differentiated glands. There was a geographical gradient of MDGI mRNA concentration in bovine mammary gland reaching a maximum in the proximal parts of the tissue. An immunohistochemical analysis with different polyclonal and peptide directed antibodies against MDGI confirmed the in situ hybridization data with respect to the tissue-specific and differentiation-dependent MDGI expression in bovine mammary gland. The results suggest a close relationship between MDGI transcription and developmental processes in the normal bovine mammary gland.
一种先前描述的生长抑制剂的互补DNA（cDNA），命名为乳腺衍生生长抑制剂（MDGI）（格罗斯，R.，和P. 朗根。1989年。载于《实验药理学手册》。即将出版）已从一个源自终末分化牛乳腺的质粒文库中克隆出来。该cDNA的测序显示有一个编码133个氨基酸的蛋白质的开放阅读框。在cDNA确定的序列与先前通过氨基酸序列分析确定的序列之间发现了六个位置的差异。Northern印迹分析显示，在终末分化的乳腺中有丰富的MDGI mRNA，而在未成熟的腺体、肝脏或胰腺中未检测到转录本的表达。利用原位杂交技术分析了MDGI在发育中的牛乳腺中的转录情况。在胚胎乳腺原基的上皮细胞、发育中小叶的上皮以及分化腺体的导管和小叶腺泡上皮细胞的终末部分中检测到MDGI mRNA的量不断增加。在牛乳腺中，MDGI mRNA浓度存在地理梯度，在组织近端部分达到最高值。用针对MDGI的不同多克隆抗体和肽导向抗体进行的免疫组织化学分析证实了原位杂交数据，即牛乳腺中MDGI的组织特异性和分化依赖性表达。结果表明MDGI转录与正常牛乳腺的发育过程之间存在密切关系。
