HANP1/H1T2, a novel histone H1-like protein involved in nuclear formation and sperm fertility.
We cloned a testis-specific cDNA from mice that encodes a histone H1-like, haploid germ cell-specific nuclear protein designated HANP1/H1T2. The HANP1/H1T2 protein was specifically localized to the nuclei of murine spermatids during differentiation steps 5 to 13 but not to the nuclei of mature sperm. HANP1/H1T2 contains an arginine-serine-rich domain and an ATP/GTP binding site, and it binds to DNA, ATP, and protamine. To investigate the physiological role of HANP1/H1T2, we generated Hanp1/H1T2-disrupted mutant mice. Homozygous Hanp1/H1T2 mutant males were infertile, but females were fertile. Although a substantial number of sperm were recovered from the epididymides, their shape and function were abnormal. During sperm morphogenesis, the formation of nuclei was disturbed and protamine-1 and -2 were only weakly detectable in the nuclei. The chromatin packaging was aberrant, as demonstrated by electron microscopy and biochemical analysis. The mutant sperm exhibited deficient motility and were not competent to fertilize eggs under in vitro fertilization conditions; however, they were capable of fertilizing eggs via intracytoplasmic sperm injection that resulted in the birth of healthy progeny. Thus, we found that HANP1/H1T2 is essential for nuclear formation in functional spermatozoa and is specifically involved in the replacement of histones with protamines during spermiogenesis. At the time of submission of the manuscript, we found an independent publication by Martianov et al. (I. Martianov, S. Brancorsini, R. Catena, A. Gansmuller, N. Kotaja, M. Parvinen, P. Sassone-Corsi, and I. Davidson, Proc. Natl. Acad. Sci. USA 102:2808-2813, 2005) that reported similar results.
Tanaka
Hiromitsu
H
Department of Science for Laboratory Animal Experimentation, Research Institute for Microbial Diseases, Osaka University, Suita, Japan.
Iguchi
Naoko
N
Isotani
Ayako
A
Kitamura
Kouichi
K
Toyama
Yoshiro
Y
Matsuoka
Yasuhiro
Y
Onishi
Masayoshi
M
Masai
Kumiko
K
Maekawa
Mamiko
M
Toshimori
Kiyotaka
K
Okabe
Masaru
M
Nishimune
Yoshitake
Y
D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine / Q000737:chemistry; D001483:Base Sequence; D001665:Binding Sites; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004822:Epididymis / Q000378:metabolism; D005260:Female; D005298:Fertility; D005306:Fertilization; D005822:Genetic Vectors; D006160:Guanosine Triphosphate / Q000737:chemistry; D006238:Haploidy; D006579:Heterozygote; D006657:Histones / Q000378:metabolism*; D006720:Homozygote; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008854:Microscopy, Electron; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology*; D010802:Phylogeny; D011479:Protamines / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013087:Spermatids / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism*; D013737:Testis / Q000378:metabolism; D013997:Time Factors; D014018:Tissue Distribution
D002843:Chromatin; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C503502:H1T2 protein, mouse; D006657:Histones; D009687:Nuclear Proteins; C513176:Prm1 protein, mouse; D011479:Protamines; C068621:protamine 2; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D004247:DNA; D001120:Arginine