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J del Mazo

Publications and source records attributed to J del Mazo.

At least 19 recordsLinked to original sources
PubMed2000

DNA polymerase lambda (Pol lambda), a novel eukaryotic DNA polymerase with a potential role in meiosis.

A new gene (POLL) encoding a novel DNA polymerase (Pol lambda) has been identified at mouse chromosome 19. Murine Pol lambda, consisting of 573 amino acid residues, has a 32% identity to Pol beta, involved in nuclear DNA repair in eukaryotic cells. It is interesting that Pol lambda contains all the critical residues involved in DNA binding, nucleotide binding and selection, and catalysis of DNA polymerization, that are conserved in Pol beta and other DNA polymerases belonging to family X. Murine Pol lambda, overproduced in Escherichia coli, displayed intrinsic DNA polymerase activity when assessed by in situ gel analysis. Pol lambda also conserves the critical residues of Pol beta required for its intrinsic deoxyribose phosphate lyase (dRPase) activity. The first 230 amino acid residues of Pol lambda, that have no counterpart in Pol beta, contain a BRCT domain, present in a variety of cell-cycle check-point control proteins responsive to DNA damage and proteins involved in DNA repair. Northern blotting, in situ hybridization analysis and immunostaining showed high levels of Pol lambda specifically expressed in testis, being developmentally regulated and mainly associated to pachytene spermatocytes. These first evidences, although indirect, suggest a potential role of Pol lambda in DNA repair synthesis associated with meiosis.

Amino Acid Sequence↗
PubMed2000

Fhx (Foxj2) expression is activated during spermatogenesis and very early in embryonic development.

FHX (FOXJ2) is a recently characterized human fork head transcriptional activator that binds DNA with a dual sequence specificity. We have cloned the cDNA for the mouse orthologue Foxj2 and characterized its expression in the gonads and along the early pre-implantation development of the mouse. In the testis, Foxj2 is expressed from pachytene spermatocytes to round spermatids, but not in spermatogonia. In addition to the germ lineage, only Sertoli cells of the testis showed expression of Foxj2. In the ovary, only granulosa cells of the follicles express the factor. Neither mature spermatozoa nor oocytes showed expression of Foxj2. Foxj2 expression is early activated in zygotic development, being detected since as early as 8-cell stage embryos. Both cell layers of the blastocyst: the trophectoderm (TE) and the inner cell mass (ICM), express Foxj2.

Amino Acid Sequence↗
PubMed2000

XYbp, a novel RING-finger protein, is a component of the XY body of spermatocytes and centrosomes.

RING-finger proteins participate in developmental processes, including gametogenesis. A fetal oocyte cDNA library was used to select genes expressed during male germ-cell differentiation. A novel RING-finger protein, XYbp (XY body protein), participating in mouse spermatogenesis has been identified. This novel gene generates a ubiquitously expressed transcript of 4.2 kb and a testis-specific one of 2.8 kb, processed by an alternative polyadenylation mechanism from a non-canonical polyadenylation signal. Transcription of XYbp is regulated during spermatocyte differentiation. The antiserum raised against the XYbp peptide demonstrated that XYbp is localised mainly in the XY bivalent of spermatocytes (XY body) and in the centrosomes of somatic and germ cells in all phases of the cell cycle. These studies indicate that we have identified a new member of the RING-finger family of proteins associated with the XY meiotic bivalent during spermatogenesis development and with the centrosomes of all cells.

Amino Acid Sequence↗
PubMed1999

Tex27, a gene containing a zinc-finger domain, is up-regulated during the haploid stages of spermatogenesis.

Tex27 is a gene encoding a protein containing a zinc-finger domain in the carboxy terminal region and a transactivation domain in the amino terminal region. The Tex27 cDNA was isolated from a subtractive library that was enriched for genes preferentially expressed during the development of the seminiferous epithelium. Northern and in situ hybridization analyses demonstrated that Tex27 is differentially expressed in the testis, showing an increased expression in the germ cells corresponding to postmeiotic stages of spermatogenesis. This expression pattern in testis has been described for other C2H2-type zinc-finger proteins in mouse and human, like CTfin51, Zpf29, Sp1, and Zpf37. RFLP-Southern assays revealed that Tex27 is conserved in mammals. The polypeptide analysis and expression pattern suggest that Tex27 is a potential transcription factor preferentially expressed in postmeiotic cells during mouse spermatogenesis.

Amino Acid Sequence↗
PubMed1999

Regulated expression of p14 (cofactor A) during spermatogenesis.

The correct folding of tubulins and the generation of functional alpha beta-tubulin heterodimers require the participation of a series of recently described molecular chaperones and CCT (or TRiC), the cytosolic chaperonin containing TCP-1. p14 (cofactor A) is a highly conserved protein that forms stable complexes with beta-tubulin which are not apparently indispensable along the in vitro beta-tubulin folding route. Consequently, the precise role of p14 is still unknown, though findings on Rb12p (its yeast homologue) suggest p14 might play a role in meiosis and/or perhaps to serve as an excess beta-tubulin reservoir in the cell. This paper investigates the in vivo possible role of p14 in testis where mitosis, meiosis, and intense microtubular remodeling processes occur. Our results confirm that p14 is more abundantly expressed in testis than in other adult mammalian tissues. Northern blot, Western blot, in situ hybridization, and immunocytochemical analyses have all demonstrated that p14 is progressively upregulated from the onset of meiosis through spermiogenesis, being more abundant in differentiating spermatids. The close correlation observed between the mRNA expression waves for p14 and testis specific tubulin isotypes beta 3 and alpha 3/7, together with the above results, suggest that p14 role in testis would presumably be associated to beta-tubulin processing rather than meiosis itself. Additional in vitro beta 3-tubulin synthesis experiments have shown that p14 plays a double role in beta-tubulin folding, enhancing the dimerization of newly synthesized beta-tubulin isotypes as well as capturing excess beta-tubulin monomers. The above evidence suggests that p14 is a chaperone required for the actual beta-tubulin folding process in vivo and storage of excess beta-tubulin in situations, such as in testis, where excessive microtubule remodeling could lead to a disruption of the alpha-beta balance. As seen for other chaperones, p14 could also serve as a route to lead excess beta-tubulin or replaced isotypes towards degradation.

Animals↗
PubMed1998

Gene expression of mouse M1 and M2 pyruvate kinase isoenzymes correlates with differential poly[A] tract extension of their mRNAs during the development of spermatogenesis.

In eukaryotes, different isoenzymes for pyruvate kinase have been characterized. M2-type Pk cDNA from a mouse fetal ovary library was isolated and differential expression for M1 and M2-types during testis development was observed. While the presence of M2 mRNAs decreases throughout the development of spermatogenesis, we deduced that M1 type expression increases in adult testis coinciding with the presence of elongating spermatids in the seminiferous epithelium. Polyadenylation tests showed a concurrent increase in the length of the polyadenylation tail of transcribed M1-type pyruvate kinase mRNAs in prepuberal to adult seminiferous tubules. A similar relationship between poly[A] tail extension and differential increase of gene expression was detected for M1-type mRNA in adult brain and muscle. Length of poly[A] tail of M2-type transcripts is shown to decrease during the development of mouse testis. These results suggest that changes in the length of the poly[A] tail of transcripts are associated with differential expression of both regulated isoenzymes during testicular development.

Animals↗
PubMed1998

Tex261, a novel gene presumably related but distinct from steroidogenic acute regulatory (StAR) gene, is regulated during the development of germ cells.

Tex261 is a new gene cloned from a subtractive cDNA library from 10-day postnatal mouse testis. Tex261 transcribes three mRNAs of 3.5, 1.6 and 1.4 kb. The 3.5 kb and 1.4 kb transcripts are expressed in different gonadal and somatic tissues analyzed. However, the 1.6 Kb transcript is only detected in testis and differentially regulated during development. This 1.6 kb mRNA is highly expressed in adult testis, with detection beginning at 15 days of postnatal life, which coincides with the presence of pachytene cells in prepuberal mouse. This expression was confirmed in pachytene cells by run-off transcription assay and by in situ hybridization. A region of 86 amino acids from the predicted Tex261 was recently reported as a part of the steroidogenic acute regulatory protein StAR gene by its sequence identity to a rat StAR cloned cDNA. We demonstrate her that, in the mouse, StAR and Tex261 are two different genes with different expected functions, yet, a high identity (43%) at amino acid level is detected in a region of 153 amino acids corresponding to a transmembrane protein.

Amino Acid Sequence↗
PubMed1997

The cytosolic aldehyde dehydrogenase gene (Aldh1) is developmentally expressed in Leydig cells.

Cytosolic aldehyde dehydrogenase, ALDH1, participates in the oxidation of different aldehydes including that of all-trans retinal to retinoic acid. The accumulation of mouse Aldh1 transcripts is characterized by having different patterns in different tissues. This paper reports the greatest expression of Aldh1 in testis and liver. It was demonstrated that in testis, Aldh1 is specifically expressed in Leydig cells and is under developmental regulation. In vitro studies of cultured Leydig TM3 cells confirmed these results though such gene expression was found not to be mediated by LH regulation. Previous investigations have associated androgen receptors, and hence the androgen insensitivity syndrome in man, with the presence of ALDH1 in genital skin fibroblasts. However, this relationship was not established in a functional cell type, as is reported here for Leydig cells. These results could suggest a model for a molecular pathway from androgen receptor to retinoic acid biogenesis in Leydig cells via the mediation of ALDH.

Aldehyde Dehydrogenase↗
PubMed1997

Developmental expression of H3.3A variant histone mRNA in mouse.

Cloning and characterization of H3.3A variant histone expression has recently been reported to be associated with meiotic development in mouse testis and ovary. Using Northern analysis and in situ hybridization, the pattern of H3.3A expression was studied during the development of different tissues. In addition to the differential expression detected in male and female meiosis, H3.3A was found to be highly expressed in preantral follicles of adult ovaries and in the basal regions of seminiferous epithelium corresponding to spermatogonia. Different patterns of expression were observed in somatic tissues, which also differed with respect to the developmental stage of the tissue. The lowest expression was detected in adult skeletal muscle. High expressions were found in foetal liver and spinal cord. These different expressions might reflect a possible function of H3.3A in cell differentiation as detected in MEL cells.

Animals↗
PubMed1995

Different developmental pattern of N-ras and unr gene expression in mouse gametogenic and somatic tissues.

Accumulation of transcripts from N-ras and unr genes was comparatively analyzed during the development of germline and somatic tissues. Northern blots on fetal and postnatal samples from somatic tissues, including brain, skeletal muscle, liver, kidney, small intestine and heart were studied together with ovaries and testis. While the expression of N-ras was rather stable all along the development of the different tissues analyzed, the expression of unr exhibited a specific pattern in some tissues. Specifically, in testis, there is a developmental regulation of the relative accumulation of the three alternative transcripts. Unr has a relative high expression in testes and heart but the accumulation seems to be different for the different size transcripts in each case. However, the expression in small intestine is practically absent in adults. From the comparative analysis of the expression of both genes, N-ras and unr, we propose that the regulation of N-ras is not directly coordinated with unr expression during the development. However, the expression of unr and its alternative transcripts is developmentally and differentially regulated in small intestine, heart and testis. The change in the pattern of accumulation during testis development from long to small alternative transcripts, could be interpreted in terms of possible alleviation of transcription interference of N-ras.

Aging↗
PubMed1995

Cloning and characterization of genes expressed during gametogenesis of female and male mice.

Isolation and initial characterization of clones from a mouse fetal ovary cDNA library are reported. In mammals, the development of female gametogenesis, including the prophase of the first meiotic division, begins in the fetus. A parallel conserved process occurs in males, from puberty onwards. We cloned cDNAs preferentially expressed in both sexes during gametogenesis considering both the meiotic programme and the non-germ cells participating in the developmental regulation of gametogenesis. From 183 clones that showed positive hybridization with adult testis and negligible hybridization with somatic probes, 32 clones were selected. After partial sequencing, 16 were found to correspond to known genes that are expressed during other programmes of differentiation and development. Sixteen clones represent novel sequences. The accumulation of corresponding transcripts was analysed by developmental northern blots during spermatogenesis, and genes expressed during gametogenesis were characterized together with others showing pleiotropic expression in different tissues. Additional specific, gametic transcripts were also detected.

Animals↗
PubMed1994

DNA methylation changes during mouse spermatogenesis.

Genomic imprinting in mammals is thought to be mediated by differences in the methylation level of cytosine residues in the genome. These differences in DNA methylation are thought to be generated during the development of the germ line. To characterize the profile of global methylation of the mouse genome during male gametogenesis, we have quantified the relative level of methylation in individual cells during meiosis and spermatogenesis. A decrease in the level of DNA methylation is observed from meiotic cells to elongated spermatids. The erasure of the somatic pattern of methylation during spermatogenesis suggests the existence of a subsequent mechanism generating the parental specific methylation patterns leading to genomic imprinting of specific alleles.

Alleles↗
PubMed1993

Construction of subtractive cDNA libraries from limited amounts of mRNA and multiple cycles of subtraction.

A new strategy to construct subtractive cDNA libraries was developed. The method was based on multiple subtraction cycles from small amounts of RNA using paramagnetic technology. An additional application of this technique is the potential to recover (and reuse) the same mRNAs or the single-stranded cDNA from the solid paramagnetic support. The result was assessed in the generation of a specific prepuberal mouse testis library.

Animals↗
PubMed1992

Microtubule-associated proteins during mouse spermatogenesis: localization of a protein immunologically related to brain MAP1B protein in the synaptonemal complex.

Monospecific polyclonal antibodies against MAP1A protein and an immunologically related brain MAP1B polypeptide were used to visualize mouse synaptonemal complexes (SCs) with immunofluorescence microscopy. Anti-MAP1A antibody recognized SCs uniformly. However, when anti-MAP1B antibody was used, a dashed pattern of staining was observed along the SCs in both autosomes and pachytene XY bivalents. After purification of SCs, immunoblots of the electrophoresed proteins revealed a polypeptide of 220 kDal, which was recognized by anti-MAP1B antibody, and two proteins of 180 kDal and 160 kDal, which were recognized by anti-MAP1A antibody. High-molecular-weight polypeptides immunologically related to microtubule-associated proteins were localized in the cell nucleus. The function of these nuclear proteins is unknown. The distribution of fluorescent signal corresponding to the 220-kDal protein during meiosis and spermiogenesis and its localization in the nuclear matrix suggest the participation of preexisting nucleoskeletal proteins in the molecular organization of the SC and its dynamics during meiotic prophase.

3T3 Cells↗
PubMed1988

Identification of centromere proteins in different mammalian cells.

The characterization of centromeric proteins is facilitated using anti-centromere antibodies present in the sera of patients with the CREST variant of scleroderma. We have employed these sera to determine whether or not those proteins are present in different mammalian species, as well as to study their tissue distribution. Here, we describe the immunofluorescent pattern and the proteins recognized by CREST sera in dividing and resting cells from mouse, rat, swine, hamster, rabbit, and man. In nuclear preparations from cultured cells, thymocytes and spermatozoa from these species, the antigens recognized by CREST sera are proteins of 18 to 20 kDa in all species tested, except in rat. Additionally, two peptides of 80 and 140 kDa were observed in human preparations. In contrast, a 50 kDa peptide is the primary protein detected by the sera in rat nuclei.

Animals↗
PubMed1987

Centromeric proteins recognized by CREST sera and meiotic chromosome segregation.

Analysis of the peptides recognized by CREST sera was carried out in different mouse tissues and cells, including spermatozoa. In all cases, a polypeptide of Mr = 18,000 was recognized by the sera and occasionally two other proteins of Mr = 80,000 and Mr = 140,000 were observed after immunoblotting of nuclear proteins. In both early and late spermatids, centromeric staining was observed after incubation and immunofluorescence with CREST sera. After detergent treatment, it was even possible to detect centromeric staining in mature spermatozoa. In spermatid cells, the immunofluorescent pattern presented a binomial distribution of the number of fluorescent spots, with a mean value around half of the haploid number of chromosomes. Since this pattern is the result of chromosome segregation after meiosis II, our data suggest that this centromeric peptide is not directly implicated in the chromosome segregation process. On the other hand, the distribution of spots after immunofluorescence suggests a different organization of centromeric components in meiosis I and meiosis II.

Animals↗
PubMed1986

Multistranded organization of the lateral elements of the synaptonemal complex in the rat and mouse.

Using electron microscopy, we have analyzed the structure of the lateral elements (LEs) of the synaptonemal complex (SC) in rat and mouse spermatocytes under different spreading conditions. Our observations indicate that in nearly 50% of the cells it is possible to detect more than one structural component of the LEs in the XY pair. When the same spreading conditions are used, the structure of the LEs is not the same in the autosomes and the XY pair. Moreover, the correlation between different spreading conditions and the detection of more than one sublateral element (subLE) was different in pachytene and diplotene spreads; it also varied depending on the species and meiotic stage. Our study supports the notion that the LEs of the SC are multistranded.

Animals↗