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T C Rodman

Publications and source records attributed to T C Rodman.

At least 37 records · Page 2Linked to original sources
PubMed1983

Proteins of de-membraned protamine-depleted mouse sperm. Homology with proteins of somatic cell nuclear envelope/matrix.

Following treatment with Triton X/1 M NaCl/2-mercaptoethanol, mouse sperm heads are divested of protamines and other basic proteins; the residual structure is one in which the general morphological organization of the decondensed chromatin and the nuclear boundaries are conserved [1]. In this study, the protein complement of that residual structure has been characterized and subdivided into two sets: 1. Those that are sperm-unique, including constituents of the sperm head that may be intrinsically nuclear (or extra-nuclear, but exceedingly adherent to the nuclear envelope). 2. Those that display corresponding electrophoretic properties and immunologic cross-reactivity with proteins of similarly treated mouse somatic cell nuclei. Among the latter are proteins of molecular weight 52, 63 and 69 kD, two of which (63 and 69 kD) appear to be homologous to polypeptides of somatic nuclear envelope/pore complex lamina. Absence from sperm nuclei of the third of the characteristic predominant triplet of somatic nuclear lamina polypeptides of mammalian cells, here designated 67 kD, indicates cell-type variation in these structures. On the other hand, the identification of homologous polypeptides in the sperm and somatic complements suggests that those are specific instances of conservation and may represent the paternal contribution to the pool of polypeptides for assembly of the envelopes of the pronuclei of the one-cell embryo.

Animals↗
PubMed1982

Mechanisms of displacement of sperm basic nuclear proteins in mammals. An in vitro simulation of post-fertilization results.

A standardized cytological preparation of mature mouse sperm has been devised to serve as an in vitro system for probing the intra-ooplasmic molecular events of transformation of the fertilizing sperm. Two parameters of the early phase of transformation in vivo are defined at the resolution of the light microscope: deletion of sperm-unique nuclear proteins, detectable by immunofluorescence, and retention of homogeneity of the residual DNA complex, with intact chromatin boundaries detectable by ethidium bromide staining. These studies show that both parameters are conserved when in vitro sperm preparations are treated with NaCl under reducing conditions. The deletion of 2 different classes of the unique basic proteins of mouse sperm nuclei is specified by the NaCl concentration: 0.7 M-NaCl displaces the non-protamine class but not the protamines, while 1 M-NaCl displaces both. On the other hand the effects of treatment with trypsin at various concentrations and intervals are less consistent with the in vivo parameters, indicating fragmentation and displacement, not only of the sperm-unique basic proteins, but also of structural proteins believed to maintain the fundamental cohesive organization of the DNA matrix. These observations suggest that mechanisms other than proteolysis, e.g. localized changes in ionic concentrations, may participate in the post-fertilization displacement of the sperm-unique nuclear proteins in vivo. This study also supports the validity of the in vitro simulation as a model with which to probe the progression of transformation of the sperm nucleus to the zygote pronucleus.

Animals↗
PubMed1981

Turnover of basic chromosomal proteins in fertilized eggs: a cytoimmunochemical study of events in vivo.

The chromosomal complements of mouse oocytes, ova, and fertilizing sperm have been studied by immunofluorescence with specific antisera to the basic protein fraction of sperm nuclei and to histones H2b and H4, and by staining with ethidium bromide. These studies support the hypothesis, previously proposed (Rodman and Barth, 1979, Dev. Biol. 68:82-95), that the chromosomes of the oocyte in maturation incorporate unique basic protein(s) similar to those incorporated during spermiogenesis. That similarity is characterized, here, by immunologic cross-reactivity. The basic proteins of the fertilizing sperm nucleus and the cross-reactive moiety of the two haploid complements of the ovum are displaced simultaneously, shortly after sperm entry. However, because the unique basic proteins incorporated into the oocyte chromosomes do not, as in the spermatogenic sequence, entirely replace the histones, the maternal chromosomes display histones H2b and H4 at all postfertilization stages examined, whereas the decondensing paternal complement, for an interval before maturation of the pronuclei, contains neither sperm basic chromosomal proteins nor histones. Sequential staining of the same specimens with ethidium bromide revealed well-organized nuclear morphology of the residual DNA complex. Those observations suggest that, for an as yet undefined period in the transformation from spermatozoal to embryonic genome, the chromatin is devoid of a complement of basic proteins.

Animals↗
PubMed1980

Metaphase chromosome associations: Colcemid distorts the pattern.

The nonrandom pattern of the spatial arrangement of chromosomes in the human metaphase complement has been resolved into separate properties by statistical analysis of matrices of ranks of interchromosomal distances averaged over sets of 25 or 50 metaphases. Assessment of the effect of a mitotic-arresting agent, Colcemid, on each of the properties of the pattern shows that those properties for which a spindle fiber dependence may be postulated are disordered by Colcemid, while the tendency for the acrocentric chromosomes to associate, attributable to their mutual participation in nucleolar organization, is not impaired by Colcemid. Furthermore, this analysis has revealed that chromosomes 21 and 22 display an exceptional propensity to be generally associative, i.e., to be close to all chromosomes; that property is obliterated by Colcemid. Since a mitotic-arresting agent is routinely used in the preparation of cells for cytogenetic analysis, that property has hitherto not been recognized.

Adult↗
PubMed1979

Serological analysis of species specificity in the high mobility group chromosomal proteins.

The non-histone chromosomal protein of the high mobility group (HMG-1) present in mouse liver was purified to homogeneity. Antibodies against this protein as well as pure HMG-1 derived from calf thymus and HMG-E purified from duck erythrocytes were elicited in rabbits. The interaction between the antibodies and the immunogens was measured by passive hemoagglutination and by quantitative microcomplement fixation. Quantitative microcomplement fixation assays revealed that the immunological distance between HMG-1 from calf thymus and HMG-1 from mouse liver and duck erythrocytes was 15. This corresponds to 3% sequence differences. It was estimated that amino acid substitution occurred at about seven positions in the polypeptide chain. Thus, HMG-1 proteins display remarkable evolutionary conservation in their primary sequence, similar to that displayed by histones H4 and H3, suggesting that their biological function is dependent on stringent structural requirements. HMG-E protein is significantly different from both HMG-1 and HMG-2 derived from calf thymus. As such, it is a protein unique to avian erythrocytes.

Amino Acid Sequence↗
PubMed1979

Life history of mouse sperm protein. Intratesticular stages.

A basic protein fraction, migrating as a single band in acetic acid-urea gel, distinct from histones, was isolated from mouse sperm collected from vasa deferentia and caudae epididymides and was used to immunize female rabbits. The presence of antibodies to the mouse sperm protein (MSP) in the rabbit antisera was demonstrated by a cytoimmunofluorescence procedure using the cells of origin of the antigenic protein, the mature mouse sperm. The specificity of the antisera was verified by fluid and gel precipitation tests and by crossed immunoelectrophoresis. The latter procedure demonstrated the presence of two antigen-antibody systems, consonant with earlier reports that the basic chromosomal protein of mouse sperm is heterogeneous. MSP antigen in situ was recognized by the specific antibodies of the rabbit antisera only after the smear of mature sperm was treated with either of two reducing agents: 2-mercaptoethanol or dithiothreitol. However, when the immunofluorescence procedure was applied to untreated smears of mouse testicular cells, spermatids of all stages from 1 to 14-15 were positive, while spermatocytes, stage 16 spermatids and spermatozoa were negative. After treatment of testes smears with reducing agent, only spermatocytes remained negative. Those observations indicate the following: (a) MSP is immunogenic in a heterologous species; (b) its antigenic sites are detectable in spermatozoa and spermatids of all stages, but not in primary spermatocytes; (c) those antigenic sites become masked at about stage 15 of spermiogenesis and may be unmasked by treatment with a reducing agent. The interpretation is made, therefore, that one or more components of MSP are assembled at the beginning of spermiogenesis and undergo an alteration in the final intratesticular stage of spermatid maturation. That alteration may be presumed to be the formation of disulfide linkages between the cysteine residues.

Animals↗
PubMed1978

Patterns of association in the human metaphase complement: ring analysis and estimation of associativity of specific chromosome regions.

The pattern of metaphase chromosome association in the human complement was studied by two methods of statistical analysis of interchromosomal distances. Those methods included ring analysis in which a characteristic position of the centromere of each chromosome relative to the center of a two dimensional representation of a metaphase complement was defined, and estimation of the capacity for associativity of each of three regions of each chromosome: the centromere (c) and the ends of each arm (p, q). The following information was obtained: 1. In general, the distance from the center is directly related to chromosome size. 2. The most notable deviation from that size-related progression is displayed by the X chromosomes. The markedly peripheral position of the X is characteristic of both X's of the female and the single X of the male. 3. The relative associativity of each chromosome of the complement is, in general, inversely related to size with an additional preferential capacity of associativity displayed by the acrocentric chromosomes. Analyses of the different inter-regional classes established that the supplementary associativity factor of the acrocentric chromosomes was inherent in their pericentromeric and p-arm regions and excluded the ends of the q arms from participation in that factor. 4. Those analyses demonstrated that the specific morphology or 'geometry' of the acrocentric chromosomes contributes little to their high relative associativity. In addition to the tendency for the c/p regions of the acrocentric chromosomes to associate with each other, presumably because of their common function in nucleolar organization, those regions also displayed a propensity to associate with the distal regions of the arms of other chromosomes. A molecular basis for that propensity other than that of ribosomal DNA is postulated to be that of other fractions of highly reiterated DNA sequences. 5. Analysis of the relative associativities of each of the three regions of the Y chromosome revealed that the Yq displays a much stronger capacity to associate with the c's of other chromosomes than does the Yc or Yp.

Adult↗
PubMed1976

RNA synthesis in preovulatory mouse oocytes.

RNA synthesis, previously shown to take place during oocyte growth, has been demonstrated throughout the growth-quiescent period preceding ovulation of the mouse oocyte. In the final 7-day preovulatory period, the level of incorporation of (5,6-3H)uridine into ovulated oocytes decreased as the interval between exposure to precursor and ovulation decreased; significant incorporation was detectable within 2 days before ovulation. Analysis of the frequency and density of label in ovarian oocytes at successive stages of meiosis in relation to the interval between adminstration of labeled precursor and collection of oocytes revealed that RNA synthesis continues up to within 2 h before GVBD.

Animals↗
PubMed1974

Human chromosome banding by Feulgen stain aids in localizing classes of chromatin.

The band patterns of human chromosomes displayed by the Feulgen stain are similar to but not identical with those of the conventional quinacrine and Giemsa preparations. The parallelism among the three is principally that of prominent negative bands that appear consistently at characteristic loci throughout a wide range of chromosome compaction. The correlation of those bands with regions of low optical density in nonbanded Fuelgen-stained chromosomes suggests that they are loci of DNA that is inherently difluse or readily labile. The instances of disparity among the patterns of the three modes of banding occur at the telomeres and at known regions of heterochromatin, and are interpreted here as reflecting the heterogeneity of the protein moieties in their reactivity to the cytochemical treatments.

Chromatin↗