Monroe R S, Huber B E
Wellcome Research Laboratories, Research Triangle Park, NC 27709.
Gene. 1994 Oct 21;148(2):261-8. doi: 10.1016/0378-1119(94)90697-1.
Northern blot analysis of rat testicular (Te) poly(A)+RNA reveals that a transcript homologous to the major form of the asialoglycoprotein receptor (ASGP-R), designated RHL-1, is expressed as early as one week postnatally and that steady-state levels are approx. 8-times higher in the Te of an 8-week-old rat (sexually mature) as compared to an 84-week-old rat (aged). Partial cDNAs encoding RHL-1 and the minor form of the ASGP-R, designated RHL-2/3, have been cloned from two rat Te/epididymal (Ep) cDNA libraries and rat Te poly(A)+RNA. Sequence analysis of the Te/Ep RHL-1 cDNA and the Te/Ep RHL-2/3 cDNA indicates that these cDNAs are identical to the forms expressed in rat liver. Western blot analysis demonstrates the presence of a 49-kDa Te/Ep RHL-1-related protein band and a 54-kDa Te/Ep RHL-2/3-related protein band in both rat Te membrane fractions (MF) and rat Ep sperm MF. The RHL-1-related protein has been localized to late-stage Te spermatids at the time of release from the seminiferous tubules and to Ep sperm in the region of the sperm tail, referred to as the middle piece. Taken collectively, these data indicate that the authentic RHL-1 and RHL-2/3 genes of the ASGP-R are expressed in late-stage spermatids; however, the Te/Ep RHL-1-related protein differs in size from the hepatic RHL-1 polypeptide, possibly indicating a specific function of the RHL-1-related protein in spermatogenesis.
对大鼠睾丸（Te）多聚腺苷酸加尾RNA（poly(A)+RNA）进行的Northern印迹分析显示，与去唾液酸糖蛋白受体（ASGP-R）主要形式同源的转录本（命名为RHL-1）在出生后一周就开始表达，并且在8周龄大鼠（性成熟）的睾丸中，其稳态水平比84周龄大鼠（老龄）的睾丸高约8倍。从两个大鼠睾丸/附睾（Ep）cDNA文库以及大鼠睾丸poly(A)+RNA中克隆出了编码RHL-1和ASGP-R次要形式（命名为RHL-2/3）的部分cDNA。对睾丸/附睾RHL-1 cDNA和睾丸/附睾RHL-2/3 cDNA的序列分析表明，这些cDNA与在大鼠肝脏中表达的形式相同。蛋白质印迹分析表明，在大鼠睾丸膜组分（MF）和大鼠附睾精子MF中均存在一条49 kDa的与睾丸/附睾RHL-1相关的蛋白条带以及一条54 kDa的与睾丸/附睾RHL-2/3相关的蛋白条带。与RHL-1相关的蛋白已定位到从生精小管释放时的晚期睾丸精子细胞以及精子尾部区域（称为中段）的附睾精子中。综合这些数据表明，ASGP-R的真实RHL-1和RHL-2/3基因在晚期精子细胞中表达；然而，睾丸/附睾RHL-1相关蛋白的大小与肝脏RHL-1多肽不同，这可能表明RHL-1相关蛋白在精子发生过程中具有特定功能。
