Differential Expression Of The MAP Kinases In The Allotetraploid Fish And Their Parents.

Mitogen-activated protein kinases (MAPK) pathway mediates signals transduction from extra-cellular environment to intracellular milieu. MAPK family consists of three major families, they are extra—cellular signal-regulated kinases(ERK), C-jun N-terminal kinases (JNK) and p38 MAPK. These kinases participate in various cellular processes such as cell proliferation, growth, development, apoptosis and cellular synchronization. In the Western blot analysis and the immunocytochemistry, the expression patterns and the activity levels as well as the special location of various MAPKs have been investigated, and the results are described as follows(1) Comparing with JNK and p38, ERK displays the strongest expression and activity in all the six tissues examined in allotetraploid fish and their distal parents, red crucian carp and common carp. JNK1 has been found in brain, liver and gonad of all three type fish, besides, JNK1 is also detected in the kidney of common carp. And JNK2 is found in brain, kidney, liver and gonad of all the three type fish. In contrast, the activity of JNK1/2 is absent in all the tissues examined. p38 kinase protein has been detected in brain, heart, muscle of all the three type fish. Furthermore, in the liver of p38 kinase is also detected, so is true in gonad of allotetraploid, red crucian carp and common carp. However, the activity of p38 kinase is only detected in heart and muscle of all the three type fish, in addition, in the kidney and liver of allotetraploid fish and red crucian carp, p38 kinase protein is also detected. The similar pattern of p38 kinase expression is also observed in the kidney of red crucian carp.(2) The expression pattern of three types of MAPK has distinct tissue specificity in allotetraploid fish, red crucian carp and common carp. Allotetraploid fish has the similar MAPK expression pattern to its father in some tissues, for instance, the expression and activity of ERK as well as the expression of p38 protein in muscle, the activity of ERK in kidney, liver and gonad, and the expression of JNK1 protein in gonad; and in some tissues, allotetraploid fish's similar pattern of MAPK expression is also detected in its mother, for instance, the expression of ERK, JNK and p38 protein in brain and heart, the expression of ERK and JNK protein in kidney as well as liver, JNK2 protein's expression in gonad, and p38 protein's expression and activity in kidney; whereas in some tissues, allotetraploid fish has its own expression characteristic, for instance, ERK protein's expression in gonad, the expression and activity of p38 protein in liver, and p38 protein's expression.(3) MAPK families are expressed in specific cells in different tissues. In brain, the expression of MAPK protein mainly exists in neurons; in heart, MAPK protein is mainly expressed in cardiac muscle cells; in muscle, MAPK protein is expressed in muscle fibers; in kidney, MAPK is located in membrane of kidney tubule; in liver, MAPK protein is mainly expressed in hepatic cells; and in gonad, MAPK protein is located in membrane of seminiferous tubules, leydig cells and oolemma.These results suggest that ERK signal pathway plays critical role in different tissues of allotetraploid, red crucian carp and common carp.