Devinoy E, Thépot D, Stinnakre M G, Fontaine M L, Grabowski H, Puissant C, Pavirani A, Houdebine L M
Laboratoire de Biologie Cellulaire et Moléculaire, Institut National de la Recherche Agronomique, Jouy en Josas, France.
Transgenic Res. 1994 Mar;3(2):79-89. doi: 10.1007/BF01974085.
The 5' flanking region (6.3 kb) of the rabbit WAP (rWAP) gene possesses important regulatory elements. This region was linked to the human growth hormone (hGH) structural gene in order to target transgene expression to the mammary gland. Thirteen lines of transgenic mice were produced. Milk could be collected from six lines of transgenic mice. In five of them, hGH was present in the milk at high concentrations ranging from 4 to 22 mg ml-1. hGH produced by the mammary gland comigrated with hGH of human origin. It was biologically active, and through its prolactin-like activity induced lactogenesis when introduced into mammary culture media. Two of these mouse lines were studied further. hGH mRNA was only detected in the mammary gland during lactation. In the seven other transgenic lines, hGH was present in the blood of cyclic females. The prolactin-like effect of hGH in these mice probably induced female sterility, and milk could therefore not be obtained. In two lines studied in more detail, the mammary gland was the main organ producing hGH, even in cyclic mice. Low ectopic expression was detected in other organs which varied from one line to the other. This was probably due to the influence on the transgene of the site of integration into the mouse genome. In the 13 lines studied, high mammary-specific hGH expression was not correlated to the transgene copy number. The rWAP-hGH construct thus did not behave as an independent unit of transcription. However, it can be concluded that the 6.3 kb flanking region of the rWAP gene contains regulatory elements responsible for the strong mammary-specific expression of hGH transgene, and that it is a good candidate to control high levels of foreign protein gene expression in the mammary gland of lactating transgenic animals.
兔乳清酸性蛋白（rWAP）基因的5'侧翼区域（6.3 kb）含有重要的调控元件。该区域与人生长激素（hGH）结构基因相连，以便将转基因表达靶向乳腺。产生了13个转基因小鼠品系。可以从6个转基因小鼠品系中收集乳汁。其中5个品系的乳汁中存在高浓度的hGH，范围为4至22 mg/ml。乳腺产生的hGH与人源hGH共迁移。它具有生物活性，当引入乳腺培养基中时，通过其催乳素样活性诱导泌乳。对其中两个小鼠品系进行了进一步研究。hGH mRNA仅在泌乳期间的乳腺中检测到。在其他7个转基因品系中，hGH存在于周期性雌性小鼠的血液中。hGH在这些小鼠中的催乳素样作用可能导致雌性不育，因此无法获得乳汁。在更详细研究的两个品系中，即使在周期性小鼠中，乳腺也是产生hGH的主要器官。在其他器官中检测到低水平的异位表达，不同品系之间有所不同。这可能是由于转基因整合到小鼠基因组的位点对其产生的影响。在所研究的13个品系中，乳腺特异性hGH的高表达与转基因拷贝数无关。因此，rWAP-hGH构建体并非作为一个独立的转录单位。然而，可以得出结论，rWAP基因的6.3 kb侧翼区域包含负责hGH转基因强乳腺特异性表达的调控元件，并且它是控制泌乳转基因动物乳腺中高水平外源蛋白基因表达的良好候选者。
