Rosbin: a novel homeobox-like protein gene expressed exclusively in round spermatids.
Mammalian spermiogenesis is a complex process occurring in a highly coordinated fashion within the seminiferous tubules. To elucidate the molecular mechanisms controlling haploid germ cell differentiation, we have isolated haploid germ cell- specific cDNA clones from a subtracted cDNA library of mouse testis. One of these cDNAs, Rosbin, is 3.2 kilobases (kb) long and has an open reading frame of 2385 nucleotides encoding a putative protein of 795 amino acid residues. A computer-mediated homology search revealed that it contained a domain similar to that of homeobox genes. Northern blot analysis revealed a 3.2-kb mRNA expressed exclusively in male germ cells. Transcription of the Rosbin gene was not observed in prepubertal testis but became detectable after Day 23. By Western blot analysis the protein encoded by this gene had a molecular mass of 89 kDa, expressing specifically in the testis and localized to the nucleus of stages IV-VIII haploid round spermatids, predominantly at stages VII-VIII of spermatogenesis. ROSBIN is associated with and is most likely phosphorylated by protein kinase A. We suggest that it plays an important role in transcriptional regulation in haploid germ cells.
Takahashi
Tohru
T
Department of Science for Laboratory Animal Experimentation, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan.
Tanaka
Hiromitsu
H
Iguchi
Naoko
N
Kitamura
Kouichi
K
Chen
Yily
Y
Maekawa
Mamiko
M
Nishimura
Hiromi
H
Ohta
Hiroshi
H
Miyagawa
Yasushi
Y
Matsumiya
Kiyomi
K
Okuyama
Akihiko
A
Nishimune
Yoshitake
Y
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D048430:Cell Shape; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D015870:Gene Expression; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D029589:Seminal Plasma Proteins / Q000235:genetics* / Q000378:metabolism*; D013087:Spermatids / Q000166:cytology* / Q000378:metabolism*; D014018:Tissue Distribution
D018076:DNA, Complementary; D018398:Homeodomain Proteins; D012333:RNA, Messenger; D029589:Seminal Plasma Proteins; C494059:rosbin protein, mouse; D017868:Cyclic AMP-Dependent Protein Kinases