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We have examined the behavior of demembranated sperm heads when injected into the germinal vesicle (GV) of amphibian oocytes. Xenopus sperm heads injected into Xenopus GVs swelled immediately and within hours began to stain with an antibody against RNA polymerase II (Pol II). Over time each spermhead became a loose mass of chromosome-like threads, which by 24-48 h resolved into individually recognizable lampbrush chromosomes (LBCs). Although LBCs derived from sperm are unreplicated single chromatids, their morphology and immunofluorescent staining properties were strikingly similar to those of the endogenous lampbrush bivalents. They displayed typical transcriptionally active loops extending from an axis of condensed chromomeres, as well as locus-specific "landmarks. " Experiments with [3H]GTP and actinomycin D demonstrated that transcription was not necessary for the initial swelling of the sperm heads and acquisition of Pol II but was required for maintenance of the lampbrush loops. Splicing was not required at any stage during formation of sperm LBCs. When Xenopus sperm heads were injected into GVs of the newt Notophthalmus, the resulting sperm LBCs displayed very long loops with pronounced Pol II axes, like those of the endogenous newt LBCs; as expected, they stained with antibodies against newt-specific proteins. Other heterologous injections, including sperm heads of the frog Rana pipiens and the zebrafish Danio rerio in Xenopus GVs, confirm that LBCs can be derived from taxonomically distant organisms. The GV system should help identify both cis- and trans-acting factors needed to convert condensed chromatin into transcriptionally active LBCs. It may also be useful in producing cytologically analyzable chromosomes from organisms whose oocytes do not go through a typical lampbrush phase or cannot be manipulated by current techniques.
Almouzni,
Nuclear assembly, structure, and function: the use of Xenopus in vitro systems.
1993, Pubmed,
Xenbase
Almouzni,
Nuclear assembly, structure, and function: the use of Xenopus in vitro systems.
1993,
Pubmed
,
Xenbase Bellini,
A zinc-binding domain is required for targeting the maternal nuclear protein PwA33 to lampbrush chromosome loops.
1995,
Pubmed Birkenmeier,
A nuclear extract of Xenopus laevis oocytes that accurately transcribes 5S RNA genes.
1978,
Pubmed
,
Xenbase Bona,
Antibodies of RNA polymerase II (B) inhibit transcription in Lampbrush chromosomes after microinjection into living amphibian oocytes.
1981,
Pubmed
,
Xenbase Bregman,
Transcription-dependent redistribution of the large subunit of RNA polymerase II to discrete nuclear domains.
1995,
Pubmed Brown,
Specific gene amplification in oocytes. Oocyte nuclei contain extrachromosomal replicas of the genes for ribosomal RNA.
1968,
Pubmed Callan,
The lampbrush chromosomes of Xenopus laevis: preparation, identification, and distribution of 5S DNA sequences.
1987,
Pubmed
,
Xenbase Dawid,
Deoxyribonucleic acid in amphibian eggs.
1965,
Pubmed Gall,
Differential synthesis of the genes for ribosomal RNA during amphibian oögenesis.
1968,
Pubmed Gurdon,
Gene transfer in amphibian eggs and oocytes.
1981,
Pubmed Gurdon,
Injected nuclei in frog oocytes: fate, enlargement, and chromatin dispersal.
1976,
Pubmed
,
Xenbase IZAWA,
The relationship between RNA synthesis and loop structure in lampbrush chromosomes.
1963,
Pubmed Krainer,
Pre-mRNA splicing by complementation with purified human U1, U2, U4/U6 and U5 snRNPs.
1988,
Pubmed Lacroix,
Monoclonal antibodies to lampbrush chromosome antigens of Pleurodeles waltlii.
1985,
Pubmed Lerner,
Monoclonal antibodies to nucleic acid-containing cellular constituents: probes for molecular biology and autoimmune disease.
1981,
Pubmed
,
Xenbase Lohka,
Formation in vitro of sperm pronuclei and mitotic chromosomes induced by amphibian ooplasmic components.
1983,
Pubmed
,
Xenbase Lohka,
Roles of cytosol and cytoplasmic particles in nuclear envelope assembly and sperm pronuclear formation in cell-free preparations from amphibian eggs.
1984,
Pubmed
,
Xenbase Lund,
In vitro synthesis of vertebrate U1 snRNA.
1989,
Pubmed
,
Xenbase Müller,
The lampbrush chromosomes of Xenopus laevis (Daudin).
1974,
Pubmed
,
Xenbase Newmeyer,
Egg extracts for nuclear import and nuclear assembly reactions.
1991,
Pubmed
,
Xenbase Paine,
The oocyte nucleus isolated in oil retains in vivo structure and functions.
1992,
Pubmed
,
Xenbase Pan,
Assembly of functional U1 and U2 human-amphibian hybrid snRNPs in Xenopus laevis oocytes.
1988,
Pubmed
,
Xenbase Paulson,
The structure of histone-depleted metaphase chromosomes.
1977,
Pubmed Postlethwait,
Zebrafish genomics: from mutants to genes.
1997,
Pubmed Prives,
Use of oligonucleotides for antisense experiments in Xenopus laevis oocytes.
1991,
Pubmed
,
Xenbase Reddy,
The cloning and characterization of a maternally expressed novel zinc finger nuclear phosphoprotein (xnf7) in Xenopus laevis.
1991,
Pubmed
,
Xenbase Roth,
Monoclonal antibodies that recognize transcription unit proteins on newt lampbrush chromosomes.
1987,
Pubmed Saitoh,
From the chromosomal loops and the scaffold to the classic bands of metaphase chromosomes.
1993,
Pubmed Scheer,
Microinjection of actin-binding proteins and actin antibodies demonstrates involvement of nuclear actin in transcription of lampbrush chromosomes.
1984,
Pubmed Schultz,
In vitro RNA synthesis in oocyte nuclei of the newt Notophthalmus.
1981,
Pubmed Snow,
Evidence for a polarized movement of the lateral loops of newt lampbrush chromosomes during oogenesis.
1969,
Pubmed Tsvetkov,
Transcription on lampbrush chromosome loops in the absence of U2 snRNA.
1992,
Pubmed
,
Xenbase Wallace,
Protein incorporation by isolated amphibian oocytes. 3. Optimum incubation conditions.
1973,
Pubmed
,
Xenbase Wu,
Small nuclear ribonucleoproteins and heterogeneous nuclear ribonucleoproteins in the amphibian germinal vesicle: loops, spheres, and snurposomes.
1991,
Pubmed
,
Xenbase Yokota,
Evidence for the organization of chromatin in megabase pair-sized loops arranged along a random walk path in the human G0/G1 interphase nucleus.
1995,
Pubmed
