ABSTRACT
Mouse protamine genes are expressed exclusively in spermatids. Mouse protamine 1 (mP1) transcriptional regulatory elements can target the expression of either marked mP1 transgenes or mP1 chimeric genes to spermatids in transgenic mice. Sequences between -40 and -465 bp relative to the transcription start site are required for expression in spermatids, whereas sequences 3' of the point of translation initiation are dispensable. mP1 transcriptional regulatory sequences were used to direct the expression of a toxic gene product to spermatids. The phenotypic consequences of toxin expression in spermatids are described.
Subject(s)
Mice, Transgenic/physiology , Protamines/physiology , Regulatory Sequences, Nucleic Acid , Seminiferous Tubules/physiology , Testis/physiology , Animals , Gene Expression Regulation , Male , Mice , RNA, Messenger/genetics , Spermatids/physiology , Tissue DistributionABSTRACT
Tissue-specific tumorigenesis can be induced in transgenic mice by the directed expression of simian virus 40 (SV40) large tumor (T) antigen. In an attempt to determine the susceptibility of haploid, round spermatids to neoplastic transformation by this oncogene, transgenic mice were generated that harbored a chimeric gene composed of the SV40 T-antigen genes fused to the 5' and 3' flanking sequences of the mouse protamine 1 gene. The transgene was expressed in round spermatids and, surprisingly, in the heart and temporal bone as well. Expression in the heart resulted in rhabdomyosarcomas that always appeared in the right atrium. Bilateral osteosarcomas developed within the petrous portion of the temporal bone. No testicular pathology was observed. T-antigen immunostaining was readily detected in tumor tissue but not in the testis. In addition, SV40 transcripts were processed differently in testis and tumor tissue. Transgenic mouse lines were established that routinely develop these tumors, and they should provide a valuable resource for studies involving cardiac and bone physiology and neoplasia. The atrial tumor cells can be maintained in vitro and some continue to display a cardiac muscle phenotype.
Subject(s)
Antigens, Viral, Tumor/genetics , Bone Neoplasms/genetics , Heart Neoplasms/genetics , Mice, Transgenic/genetics , Oncogenes , Protamines/physiology , Spermatids/physiology , Animals , Bone Neoplasms/pathology , Gene Expression Regulation , Heart Neoplasms/pathology , Male , Mice , RNA Processing, Post-Transcriptional , RNA, Messenger/genetics , Simian virus 40/geneticsSubject(s)
Gene Expression Regulation , Protamines/physiology , Spermatogenesis , Spermatozoa/physiology , Actins/genetics , Amino Acid Sequence , Animals , Base Sequence , Cytoplasm/physiology , Male , Molecular Sequence Data , Nuclear Proteins/physiology , RNA, Messenger/genetics , Tubulin/geneticsSubject(s)
Chromatin/physiology , Spermatogenesis , Spermatozoa/cytology , Animals , Chromatin/analysis , Chromatin/ultrastructure , Chromosomal Proteins, Non-Histone/physiology , DNA/metabolism , Histones/physiology , Humans , Male , Meiosis , Nuclear Proteins/metabolism , Nucleic Acid Conformation , Nucleoproteins/metabolism , Poly Adenosine Diphosphate Ribose/physiology , Poly(ADP-ribose) Polymerases/metabolism , Protamines/physiology , Protein Biosynthesis , RNA/biosynthesis , RNA, Heterogeneous Nuclear/biosynthesis , Spermatids/analysis , Spermatozoa/analysis , Spermatozoa/ultrastructure , Transcription, GeneticABSTRACT
Enterobacterial common antigen isolated by two independent extraction procedures was found to precipitate with a number of basic or hydrophobic proteins. Complexes of enterobacterial common antigen with protamine sulfate, with methylated bovine serum albumin or with a fraction of outer membrane proteins of two different Shigella wild types proved to be highly immunogenic in rabbits upon intravenous immunization, in contrast to the enterobacterial common antigen preparations by themselves. This explains why crude isolates of enterobacterial common antigen usually are good immunogens in contrast to the isolated antigen, which was described to be either not or only very poorly immunogenic.
Subject(s)
Antibodies, Bacterial/biosynthesis , Antigens, Bacterial/immunology , Enterobacteriaceae/immunology , Proteins/physiology , Bacterial Proteins/physiology , Membrane Proteins/physiology , Protamines/physiology , Serum Albumin, Bovine/physiology , Shigella/analysisABSTRACT
Specific contacts between the crossinteracting histones effectively prevent their protamine-mediated displacement from nucleoproteins revealing a complex competition pattern not expected from their relative affinities to DNA. Histone H1 is the only species freed under a variety of conditions if native chromatin is used; the results found with chromatins obtained by conventional methods reflect the extent to which histone redistribution has occurred. It is concluded that the events occurring during spermiogenesis must be apt to disrupt histone interactions found in the nucleosomes. The possible role of a protamine phosphorylation/dephosphorylation mechanism is discussed on the basis of comparative experiments with protamines phosphorylated to different extents.