Meichroacidin containing the membrane occupation and recognition nexus motif is essential for spermatozoa morphogenesis.
Meichroacidin (MCA) is a highly hydrophilic protein that contains the membrane occupation and recognition nexus motif. MCA is expressed during the stages of spermatogenesis from pachytene spermatocytes to mature sperm development and is localized in the male meiotic metaphase chromosome and sperm flagellum. MCA sequences are highly conserved in Ciona intestinalis, Cyprinus carpio, and mammals. To investigate the physiological role of MCA, we generated MCA-disrupted mutant mice; homozygous MCA mutant males were infertile, but females were not. Sperm was rarely observed in the caput epididymidis of MCA mutant males. However, little to no difference was seen in testis mass between wild-type and mutant mice. During sperm morphogenesis, elongated spermatids had retarded flagellum formation and might increase phagocytosis by Sertoli cells. Immunohistochemical analysis revealed that MCA interacts with proteins located on the outer dense fibers of the flagellum. The testicular sperm of MCA mutant mice was capable of fertilizing eggs successfully via intracytoplasmic sperm injection and generated healthy progeny. Our results suggest that MCA is essential for sperm flagellum formation and the production of functional sperm.
Tokuhiro
Keizo
K
TANAKA Project, Center for Advanced Science and Innovation, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
Hirose
Mika
M
Miyagawa
Yasushi
Y
Tsujimura
Akira
A
Irie
Shinji
S
Isotani
Ayako
A
Okabe
Masaru
M
Toyama
Yoshiro
Y
Ito
Chizuru
C
Toshimori
Kiyotaka
K
Takeda
Ken
K
Oshio
Shigeru
S
Tainaka
Hitoshi
H
Tsuchida
Junji
J
Okuyama
Akihiko
A
Nishimune
Yoshitake
Y
Tanaka
Hiromitsu
H
D020816:Amino Acid Motifs / Q000235:genetics; D000818:Animals; D002347:Carps / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D033481:Chromosomes, Mammalian / Q000235:genetics / Q000378:metabolism; D002938:Ciona intestinalis / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004822:Epididymis / Q000378:metabolism; D005298:Fertility / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology*; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D010587:Phagocytosis / Q000502:physiology; D012708:Sertoli Cells / Q000378:metabolism; D013082:Sperm Tail / Q000378:metabolism*; D013087:Spermatids / Q000378:metabolism; D013091:Spermatogenesis / Q000502:physiology*; D014998:Y Chromosome / Q000235:genetics / Q000378:metabolism
D004268:DNA-Binding Proteins; C112368:Tsga2 protein, mouse