An alternative pathway of histone mRNA 3′ end formation in mouse round spermatids

• Published in: Nucleic acids research Vol. 22; no. 15; pp. 3160 - 3166
• Main Authors: Moss, Stuart B., Ferry, Ruth A., Groudine, Mark
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 11.08.1994
• Subjects: Animals; Base Sequence; Biological and medical sciences; Blotting, Northern; DNA Replication; DNA, Complementary - chemistry; Fundamental and applied biological sciences. Psychology; Histones - genetics; Male; Mammalian male genital system; Mice; Molecular Sequence Data; Morphology. Physiology; Poly A - metabolism; Polyribosomes - metabolism; RNA, Messenger - biosynthesis; RNA, Messenger - chemistry; Spermatids - metabolism; Transcription, Genetic; Vertebrates: reproduction; 3'-End; Histone H2A; Spermiogenesis; Transcription; Rodentia; Genetical translation; Spermatid; Vertebrata; Mammalia; Messenger RNA; Mouse; Polyadenylation; Histone H3; Nuclear protein
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/22.15.3160

During mammalian spermiogenesis, the post-meiotic stage of spermatogenesis, histones are replaced by protamines on the DNA. Despite this histone elimination, novel polyadenylated histone transcripts were detected in mouse round spermatids. Sequence analysis of a spermatid-specific H2a cDNA clone indicated that it was derived from a mRNA of a replication-dependent histone gene even though its transcript was not polyadenylated in somatic and earlier spermatogenic cells. In round spermatids, both the hairpin and purine-rich elements in the 3′ untranslated region of the somatic pre-mRNA were retained in the mature poly(A)+ mRNA transcripts. Polyadenylation occurred downstream of the purine-rich element and was not preceded by the somatic AATAAA polyadenylation signal sequence. While polyadenylated histone transcripts from replication-dependent genes have been observed previously in somatic cells, characteristics of this type of 3′-end formation in mammalian round spermatids were unique. In particular, a specific replication-dependent H2a gene was transcribed either as a polyadenylated or nonpolyadenylated transcript in these cells, suggesting that the type of transcript present was dependent on the RNA sequence. Finally, both poly(A)− and poly(A)+ mRNAs were found on polyribosomes from round spermatids, indicating that histones were being translated in these cells and that the polyadenylation status of these transcripts did not affect their translatability.