Manuel Martínez Valdivia

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The chromosomes of the Indian muntjac (Muntiacus muntjak vaginalis) are unique among mammals due to their low diploid number (2N = 6 female, 7 male) and large size. It has been proposed that the karyotype of this small Asiatic deer evolved from a related deer the Chinese muntjac (Muntiacus reevesi) with a diploid chromosome number of 2n = 46 consisting of(More)
A novel protein has been identified which may serve a key function in nucleating spindle microtubule growth in mitosis. This protein, called centrophilin, is sequentially relocated from the centromeres to the centrosomes to the midbody in a manner dependent on the mitotic phase. Centrophilin was initially detected by immunofluorescence with a monoclonal,(More)
Dissection of human centromeres is difficult because of the lack of landmarks within highly repeated DNA. We have systematically manipulated a single human X centromere generating a large series of deletion derivatives, which have been examined at four levels: linear DNA structure; the distribution of constitutive centromere proteins; topoisomerase IIalpha(More)
A pituitary hormone, somatolactin (SL), belonging to the GH/PRL family, is produced in the intermediate lobe of the teleost pituitary. The function of this protein is uncertain. Clones coding for SL were isolated and sequenced from a gilthead seabream pituitary cDNA expression library. The nucleotide sequence of the larger cDNA isolated was 1.5 kb(More)
Normal distribution of chromosomes to daughter cells is insured by the proper functioning of the spindle. Homozygosity for a semi-lethal mutation of Drosophila melanogaster (abnormal spindle) altering this structure has the following effects: the mitotic cycle is arrested in metaphase, leading to a high frequency of polyploid cells; sex chromosome(More)
Growth hormone (GH) and insulin-like growth factors (IGFs) play a major role in fish development and metabolism, and several studies have allowed discernment of a complex and tissue-specific collection of salmonid IGF-I transcripts (Ea-4, Ea-3, Ea-2, Ea-1), which are the result of the alternative splicing of the E-domain region. However, the pattern of(More)
Antibodies from the serum of patients with the autoimmune disease scleroderma CREST were used to investigate the association and distribution of kinetochores in mouse cells during meiosis and spermiogenesis. The pattern of indirect immunofluorescent staining in pachytene nuclei indicated that each autosomal bivalent contains one fluorescent spot. Throughout(More)
We have partially isolated the kinetochore and associated centromeric structures from mammalian metaphase chromosomes. Human autoantibodies from scleroderma CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia) patients were used as immunofluorescent probes to monitor fractionation. The procedure includes digestion(More)
Regulation of somatolactin (SL) and the somatotropic axis was examined year-around at three different stocking times (spring, summer, and autumn) in a Mediterranean fish, the gilthead sea bream (Sparus aurata). The overall timing of plasma growth hormone (GH) increase was similar among trials (late spring-early summer), but the range of variation(More)
Growth hormone (GH), prolactin (PRL) and somatolactin (SL) are single chain proteins structurally and functionally related. Fish PRL and GH receptors (PRLR, GHR) have been characterized in several fish species. There is limited evidence of fish PRLR isoforms, but emerging data support the existence of different GHR variants. In gilthead sea bream, black sea(More)