Congress Abstracts - Society for Developmental Biology

Program/Abstract # 168
Characteristic patterns of the incorporation of BrdU during DNA replication in different cells of the seminiferous epithelium
of the rat
Ortiz, Rosario; Muñoz, Israel; Echeverría, Olga; Vazquez-Nin, Gerardo (Universidad Nacional Autonoma de Mexico, Mexico)
In the seminiferous epithelium we study the morphologic characteristics of DNA replication in rat spermatogonia and spermatocytes
in preleptotene by means of immunodetection of the incorporation of bromodeoxiuridin (BrdU) during 30 min until 24 hours. The
results show three patterns of labeling independently of their age. One characterized by foci, localized primarily to the periphery of the
nucleus of spermatogonias type A and B, a second pattern in which the label is distributed in all the nuclear volume of preleptotene
spermatocytes and finally, a pattern present in spermatocytes in leptotene, in which the label is restricted to only a region located
anywhere the nucleus. These incorporation patterns can be used to identify the different cells types of the germinal line in phase S,
which otherwise is particularly difficult during puberty. This work was supported by the grant : PAPIIT IN203308 UNAM
Program/Abstract # 169
Immunodetection of SYCP1 and SYCP3 during the first spermatogenic wave Wistar rat
Valenzuela, Yunuen; Ortiz, Rosario; Echeverría, Olga; Vazquez-Nin, Gerardo (Universidad Nacional Autonoma de Mexico, Mexico)
The primary spermatocytes have an exclusive structure called synaptonemal complex (SC), which is essential for the synapsis of
homologous chromosomes. The SYCP1 (Synaptonemal Complex Protein 1) and SYCP3 (Synaptonemal Complex Protein 3) are
involved in the assembly of the SC. It has been shown that the absence of any of the proteins constituting the SC causes alterations
that lead to cell death. The aim of the present work is to characterize the distribution of SYCP1 and SYCP3 by means of
immunodetections at light microscope level in prepubertal Winstar rats. In 13 days old rats labeling for SYCP3 is present in cells in
preleptotene and leptotene stages. In 16 days old rats increases the number of cells positive to SYCP3 and appear cells positive to
SYCP1, indicating the presence of zygotenes and early pachytenes. In 27 days old rats late pachytene and early spermatids are also
present. In 16 and 27 days old rats some primary spermatocytes has an atypical distribution of SYCP3 labeling in the nuclear
periphery. This distribution of the SYCP3 labeling may indicate alterations in the SC assembly that could lead to apoptosis of primary
spermatocytes. This work was supported by the grant : PAPIIT IN203308 UNAM
Program/Abstract # 170
Cell death in atretic granulosa cells
Escobar, Maria; Vazquez-Nin, Gerardo; Casasa, Sofia; Garcia, Gethsemany; Echeverría, Olga (Universidad Nacional Autonoma de
Mexico, Mexico)
Follicular atresia is the process by which most of the follicles existing in the ovary at birth are lost. Apoptosis cell death is involved in
the follicular atresia in mammals, especially in granulosa cells. However we have observed that in all stages of atresia, numerous
granulosa cells have characteristics different to the classical apoptosis. The aim of the present work is to characterize the process of
cell death of granulosa cells during the atresia of adult rats. We have employed a detailed ultrastructural analysis, correlated with
TUNEL assay as well as active caspase-3, LC3 and Beclin-1 immunolocalizations. We also evaluated the mRNA of Caspase-3 and
LC3 by RT-PCR, as well as active caspase-3 and LC3 by Western Blot analyses. DNA fragmentation was demonstrated by means of
electrophoreses in agarose gel. Our ultrastructural, immunohistochemical and molecular results demonstrate that granulosa cells death
involves molecular mechanisms belonging to apoptosis and autophagy cell death, and in lesser degree cells are eliminated by both
types of cell death simultaneously. This work was supported by the grant of CONACYT 180526.
Program/Abstract # 171
TACC3 is a crucial protein for bovine oocyte meiosis
Mahdipour, Mahdi; Leitoguinho, Ana Rita; Zacarias, Ricardo; Luteijn, Maartje; Van Tol, Helena; Ketting, Rene; Roelen, Bernard
(Utrecht, Netherlands)
Transforming acidic coiled– coiled (TACC) proteins belong to a cluster of proteins associated with various cancers. Mammals express
three TACC proteins: TACC1, TACC2 and TACC3 coded by three genes. TACC3 deficient mice displayed embryonic lethality,
reduced cell number and mitotic defects which suggest an important role for this protein during early cell division. Although d
epletion of TACC3 during meiotic oocyte maturation in mice resulted in inhibition of polar body extrusion and arrested meiosis I, its
function during mammalian meiosis remains relatively unknown. In this project, with the help of quantitative RT-PCR we perceived
that TACC3 transcript was expressed during bovine oocyte maturation and early embryo development until the 8 cell stage but
decreased to non-detectable levels at the morula and blastocyst stages. Whole mount immunofluorescence on oocytes revealed that
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