Phosphorylated SAP155, the spliceosomal component, is localized to chromatin in postnatal mouse testes.
SAP155 is an essential component of the spliceosome and its phosphorylation is required for splicing catalysis, but little is known concerning its expression and regulation during spermatogenesis in postnatal mouse testes. We report that SAP155 is ubiquitously expressed in nuclei of germ and Sertoli cells within the seminiferous tubules of 6- and 35-day postpartum (dpp) testes. Analyses by fractionation of testes revealed that (1) phosphorylated SAP155 was found in the fraction containing nuclear structures at 6 dpp in amounts much larger than that at other ages; (2) non-phosphorylated SAP155 was detected in the fraction containing nucleoplasm; and (3) phosphorylated SAP155 was preferentially associated with chromatin. Our findings suggest that the active spliceosome, containing phosphorylated SAP155, performs pre-mRNA splicing on chromatin concomitant with transcription during testicular development.
Eto
Ko
K
Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan. etoko@gpo.kumamoto-u.ac.jp
Sonoda
Yoshiyuki
Y
Jin
Yuji
Y
Abe
Shin-ichi
S
D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002843:Chromatin / Q000378:metabolism*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D012322:RNA Precursors / Q000378:metabolism; D000072260:RNA Splicing Factors; D017413:Ribonucleoprotein, U2 Small Nuclear / Q000378:metabolism*; D017381:Spliceosomes / Q000378:metabolism*; D013737:Testis / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D014158:Transcription, Genetic
D002843:Chromatin; D010750:Phosphoproteins; D012322:RNA Precursors; D000072260:RNA Splicing Factors; D017413:Ribonucleoprotein, U2 Small Nuclear; C491799:Sf3b1 protein, mouse