Studies on a new growth factor under the control of retinoic acid, midkine (MK)

MK中S-S-桥的排列确定如下：C_<12>-C_<36>，C_-<20>C_<45>，C_-<27>C_<49>，C_-<54>C_<91>，C_-<69>C_<101>，表示MK由两个域组成。小鼠MK基因（MK2型）的上游2kb序列连接到CAT基因，并转移到F9细胞。2kd sequence mediated CAT gene activation on retinoic acid treatment。一种视网膜酸反应性增强剂在2kb片段中被发现。核心元素对视网膜酸受体结合序列的同源性有很高的分量，对RXR和RAR异聚物有很高的分量。MK具有各种embryonic neurons的神经活性，如来自spinal cord和dorsal root ganglion。MK绑定到合成酶，并可达到85 kDa的便携式MK受体。MK表达在许多人类甲状腺素中被发现，包括Wilm的肿瘤、Hepatocellular甲状腺素瘤和Pancreatic甲状腺素瘤。Senile plaqule in the brain of Arzheimer disease patients invariable expressed MK.As above， MK是一个重要的生长因子，在retinoic acid的控制下，并且可能在人类疾病的伦理学中发生。

The arrangement of -S-Sbridges in MK was determined as follows : C_<12>-C_<36>, C_<20>-C_<45>, C_<27>-C_<49>, C_<54>-C_<91>, C_<69>-C_<101>, indicating that MK is composed of two domains. The 2kb upstream sequence of mouse MK gene (MK2 type) was linked to CAT gene and transfected to F9 cells. The 2kd sequence mediated CAT gene activation upon retinoic acid treatment. A retinoic acid responsive enhancer was found in the 2kb fragment. The core element has high dergee of homology to retinoic acid receptor binding sequence, and indeed bound to RXR・RAR heterodimer. MK had neurotrophic activity to various embryonic neurons such as from spinal cord and dorsal root ganglion. MK bound to syndecan and to a putative MK receptor of 85 kDa. MK expression was increased in many human carcinomas including Wilm's tumor, hepatocellular carcinoma and pancreatic carcinoma. Senile plaqule in the brain of Arzheimer disease patients invariable expressed MK.As above, MK is an important growth factor under the control of retinoic acid, and is probably involved in ethiology of human diseases.