DOI Page / Citation link:
https://doi.org/10.11588/diglit.48120#0042
24 Molecular and Cell Biology of Autoantibodies and Autoimmunity
SC formation appears to be an essential prerequisite for chromosome pairing,
recombination and homologue disjunction.
Immunofluorescent staining of pachytene cells localized the autoantigen to
the central element or the transverse filaments of the SC but not to the lateral
elements. In leptotene and zygotene spermatocytes, antigenic SC structures are
not at all detectable. The earliest stage of meiotic prophase which contains the
SC antigen is pachytene. At higher magnification, the antigenic SC structure
shows a relatively uniform longitudinal segmentation. The SC ends which are
known to attach to the nuclear envelope are characterized by a thickened segment
of variable size. The longitudinal segmentation of the SCs does not correspond
to the chromomere pattern of pachytene bivalents; most probably, it reflects a
structural or functional property of the SCs themselves. Specific antibody label-
ing is confined to the SC at synapsis. The lateral elements of unpaired
homologues at leptotene and zygotene as well as the unpaired axes of the X and
Y chromosomes during pachytene are not labeled. The antigenic SC structure is
definitely lost during diplotene. Therefore, it can be hypothesized that the SC an-
tigen is involved in stage-specific processes such as chromosome pairing and
recombination.
Cytochemical tests revealed the SC antigen to be a hydrophobic non-histone
protein bound to DNA. It cannot be extracted by balanced salt solutions, high
ionic strength solutions and non-ionic detergents. The nature of the SC antigen
and its insolubility are reminiscent of the biochemical composition of the nuclear
skeleton and the mitotic chromosome scaffold, respectively.
An unusual characteristic of the SC autoantigen is its species specificity. Pa-
tients were found whose sera selectively labeled the SCs of human, mouse or
newts. Nevertheless, most anti-SC antisera demonstrate minor cross-reactions be-
tween different pachytene cell substrates indicating that the SCs share some ubi-
quitous antigenic components.
Immunolocalization and Number of Transcriptionally Active rRNA
Genes in Vertebrate Cells
T. Haaf and M. Schmid
Department of Human Genetics, University of Wurzburg, Wurzburg, FRG
Under the action of the adenosine analogue DRB, the normally compact
nucleoli are spread through the nuclear interior forming several beaded strands.
SC formation appears to be an essential prerequisite for chromosome pairing,
recombination and homologue disjunction.
Immunofluorescent staining of pachytene cells localized the autoantigen to
the central element or the transverse filaments of the SC but not to the lateral
elements. In leptotene and zygotene spermatocytes, antigenic SC structures are
not at all detectable. The earliest stage of meiotic prophase which contains the
SC antigen is pachytene. At higher magnification, the antigenic SC structure
shows a relatively uniform longitudinal segmentation. The SC ends which are
known to attach to the nuclear envelope are characterized by a thickened segment
of variable size. The longitudinal segmentation of the SCs does not correspond
to the chromomere pattern of pachytene bivalents; most probably, it reflects a
structural or functional property of the SCs themselves. Specific antibody label-
ing is confined to the SC at synapsis. The lateral elements of unpaired
homologues at leptotene and zygotene as well as the unpaired axes of the X and
Y chromosomes during pachytene are not labeled. The antigenic SC structure is
definitely lost during diplotene. Therefore, it can be hypothesized that the SC an-
tigen is involved in stage-specific processes such as chromosome pairing and
recombination.
Cytochemical tests revealed the SC antigen to be a hydrophobic non-histone
protein bound to DNA. It cannot be extracted by balanced salt solutions, high
ionic strength solutions and non-ionic detergents. The nature of the SC antigen
and its insolubility are reminiscent of the biochemical composition of the nuclear
skeleton and the mitotic chromosome scaffold, respectively.
An unusual characteristic of the SC autoantigen is its species specificity. Pa-
tients were found whose sera selectively labeled the SCs of human, mouse or
newts. Nevertheless, most anti-SC antisera demonstrate minor cross-reactions be-
tween different pachytene cell substrates indicating that the SCs share some ubi-
quitous antigenic components.
Immunolocalization and Number of Transcriptionally Active rRNA
Genes in Vertebrate Cells
T. Haaf and M. Schmid
Department of Human Genetics, University of Wurzburg, Wurzburg, FRG
Under the action of the adenosine analogue DRB, the normally compact
nucleoli are spread through the nuclear interior forming several beaded strands.