ABSTRACT
Although Lewis X (LeX) and Lewis Y (LeY) antigens were thought to play important roles in fertility, fucosyltransferase (Fut)-deficient (Fut1, Fut2 and Fut4) mice which lack LeX or LeY antigen are still fertile. In the present study, the Fut-deficient and wild-type mice were used to measure the expression of Fut mRNA along the mouse male reproductive tract and determine the role of each Fut in the biosynthesis of LeX/LeY antigens, which are conjugated to glycoproteins in the male reproductive system. LeX/LeY-containing glycoproteins were detected in the epididymis, vas deferens, seminal vesicle and coagulating gland, but not in the testis. We demonstrate that the synthesis of LeY-containing glycoproteins in the epididymis and vas deferens is catalyzed by Fut1 and Fut4. In the seminal vesicle and the coagulating gland, they are mainly synthesized by Fut2 and an α-(1,3)-Fut, but not Fut4. The synthesis of LeX-containing glycoproteins in the middle caput epididymis is catalyzed by Fut4 and by Fut4 and Fut2 in the seminal vesicle. We provide evidence that LeX is synthesized in the coagulating gland by Fut9. We found that the lack of activity by one Fut does not completely inhibit LeX/LeY antigen expression in the male reproductive tract. This redundancy may help to explain why in vivo studies with Fut-deficient mice do not support the presumption that LeX/LeY antigens play important roles in male fertility. We provide details regarding the phenotypes of established Fut-deficient mice and lay the foundation for elucidating the functions of LeX/LeY antigens in other aspects of the male reproductive system.
Subject(s)
Fertility , Fucosyltransferases , Lewis Blood Group Antigens , Lewis X Antigen , Animals , Fertility/genetics , Fucosyltransferases/genetics , Fucosyltransferases/metabolism , Gene Expression , Genitalia, Male/physiology , Genitalia, Male/ultrastructure , Glycoproteins/genetics , Glycoproteins/metabolism , Glycosylation , Humans , Lewis Blood Group Antigens/genetics , Lewis Blood Group Antigens/metabolism , Lewis Blood Group Antigens/ultrastructure , Lewis X Antigen/genetics , Lewis X Antigen/metabolism , Lewis X Antigen/ultrastructure , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Phenotype , Reproduction/geneticsABSTRACT
Using immunocytochemistry, morphometry and electron microscopy, we have investigated the distribution and characteristics of CD15-immunoreactive (IR) neurons in the guinea pig retina. In the present study, two types of amacrine cells, including interplexiform cells in the inner nuclear layer (INL) and some cells in the ganglion cell layer (GCL), were labeled with anti-CD15 antisera. Type 1 amacrine cells had large somata located in the INL, with long and branched processes ramifying mainly in strata 4 and 5 of the inner plexiform layer (IPL). Somata of type 2 cells had smaller diameters, and were also located in the INL. Their processes stratified in stratum 1. The densities of type I and type 2 amacrine cells increased from 152.8+/-36.7/mm2 and 160.6+/-61.7/mm2 in the peripheral retina, to 404.3+/-41.5/mm2 and 552.2+/-72.2/mm2 in the central retina, respectively. Cells in the GCL exhibiting CD15 immunoreactivity were rarely observed. Colocalization experiments, using consecutive semi-thin sections, demonstrated that these CD15-IR amacrine cells exhibited gamma-aminobutyric acid (GABA) immunoreactivity. In addition, the processes of the type 1 cells formed one member of the postsynaptic dyads that are formed in the axon terminals of rod bipolar cells. Most of these processes made reciprocal synapses back to the axon terminals of the rod bipolar cells. Thus, CD15-IR amacrine cells constitute a subpopulation of GABAergic amacrine cells in the guinea pig retina, and the type 1 cells among them provide the inhibitory input to rod bipolar cells.
