Rs. Monroe et Be. Huber, THE MAJOR FORM OF THE MURINE ASIALOGLYCOPROTEIN RECEPTOR - CDNA SEQUENCE AND EXPRESSION IN LIVER, TESTIS AND EPIDIDYMIS, Gene, 148(2), 1994, pp. 237-244
Northern blot analysis of poly(A)(+)RNAs isolated from mouse liver or
mouse testis (Te)/epididymis (Ep) reveals that both tissues express 1.
5- and 7.5-kb transcripts which have extensive homology to the major f
orm of the rat asialoglycoprotein receptor (ASGP-R). In situ hybridiza
tion studies have localized the expression of this ASGP-R-like transcr
ipt to late-stage sperm from Te and Ep of several different strains of
mice. Swiss Webster mice express this ASGP-R-like transcript in late-
stage spermatids at the time of release into the seminiferous tubule a
nd in Ep sperm, while Balb/C, NIH Swiss and C57Bl/6 mice express this
ASGP-R-like transcript predominantly in Ep sperm. cDNAs containing the
entire coding region for this ASGP-R-like transcript have been cloned
from mouse liver and mouse Te/Ep. These cDNAs are 100% identical in t
he coding region and 3'-untranslated region (UTR), but differ in the 5
'-UTR. The gene encoding these cDNAs is called MHL-1, designating the
major form of the mouse ASGP-R. The deduced amino acid (aa) sequence o
f MHL-1 shares 88% homology to the rat hepatic (He) lectin form 1 (RHL
-1) and 78% homology to the human asialoglycoprotein receptor form 1 (
H1). The three sites for N-linked glycosylation in the RHL-1 sequence
are all conserved in the deduced MHL-1 sequence. Taken collectively, t
hese data describe the cloning and sequencing of the MHL-1 cDNA and il
lustrate its deduced aa homology to RHL-1 and H1. Most importantly, th
ese data show that mouse late-stage spermatids and Ep sperm express th
e authentic MHL-1 gene, suggesting this receptor may have an important
role in spermatogenesis, in addition to its He function.