Biology Reference
In-Depth Information
Fig. 4.1 Schematic representation of non-rodent sperm: showing sperm head with DNA and
nuclear matrix proteins and the centriole complex. The sperm's centriole complex consists of two
perpendicularly oriented centrioles. The centriole close to the nucleus is termed the proximal
centriole and contains sparse centrosomal material that will become important for microtubule
nucleation of sperm aster, zygote aster, and mitotic apparatus in the fertilized oocyte while the
centriole associated with the sperm tail (distal centriole; basal body) will not participate in the
embryo's microtubule formations and will be subjected to degeneration along with the sperm tail
after fertilization
sperm head decondenses and the centriole-centrosome complex matures within
the zygote to become a division-competent centrosome that forms the mitotic
spindle poles and separates chromosomes equally to the dividing daughter cells, as
detailed in
Sect. 3
of this chapter.
Excellent electron micrographs are available on the centriole complex in human
sperm that have been presented in several original papers and review articles
(Chemes
2000
; Chemes and Rawe
2003
; Mitchell et al.
2006
; Rawe et al.
2002
;
Rawe and Chemes
2009
; Sathananthan et al.
1991
,
1996
,
2001
; Sathananthan
1997
, Sathananthan
2009
) displaying clear structural associations between the
sperm nucleus and the proximal centriole. Examples are presented in
Chaps. 2
and
5
of this topic (by Hector E. Chemes and A. Henry Sathananthan, respectively),
providing remarkable detail of normal structure and structural abnormalities in the
proximal centriole-sperm nucleus associations that impact fertilization. Structural
abnormalities and dysfunctions associated with male factor infertility have been
documented and it has also been shown that in some cases of infertility centriole-
nuclear detachment sites are impaired (Liska et al.
2009
; Kierszenbaum et al.
2011
). While morphological abnormalities have clearly been identified as under-
lying causes for sperm centriole-centrosomal dysfunctions, molecular abnormal-
ities have been determined by using a variety of molecular methods including
immunoblotting techniques (Bohring and Krause
2003
; reviewed in Schatten and
Sun
2009a
,
2009b
). Several studies have been performed on human sperm that
correlate decreased c-tubulin and decreased centrin to lower fertilizability in
humans (Hinduja et al.
2008
;
2010
) and correlated below-normal quantities to
decreased sperm aster formation and developmental capacity, as also discussed by
Comizzoli and Wildt in
Chap. 3
of this topic.
While recent research has focused on the sperm's centrosome complex as
causes of infertility, studies related to nuclear components within the sperm
