1,721,074 research outputs found
Two plasma membrane antigens of testicular Sertoli cells and H-2-restricted versus unrestricted lysis by female T cells
No full textSertoli cell-only seminiferous tubules of sterile XX,Sxrl-male mice served as an excellent source of pure Sertoli cells. When H-2-compatible female mice were immunized 3 times with these Sertoli cells, resulting antibodies recognized two antigens on the plasma membrane of testicular Sertoli cells. They were male-specific, but ubiquitously expressed H-Y antigen and the cell lineage-specific antigen which Sertoli cells shared with ovarian follicular cells. Doubly primed (2 or 3 times in vivo, and once in vitro) cytotoxic T cells from these females lysed target Sertoli cells in both H-2-restricted and nonrestricted manners. While H-2-restricted killings were attributable to H-Y antigen, further work is needed to identify the Sertoli follicular cell lineage-specific antigen as the cause of H-2-nonrestricted killings
Funzione organogenetica dell’Antigene H-Y secreto da cellule Daudi su gonadi indifferenziate di embrione umano XX
No full textIsolation and characterization of cDNA clones for the rat X-chromosome linked PGK: a comparative analysis of the nucleotide frequencies and of the amino acids composition
No full textThe nucleotide sequence of cDNA clones containing the coding region for rat X-chromosome linked phosphoglycerate kinase: evolutionary conservation of amino acids in the substrate-binding cleft
No full textStructural analysis of the gene for the beta chain of the antigen specific receptor of mammalian T-lymphocytes
No full textThe antigen specific receptor of T cells (TCR) is composed of alpha and beta chains and is normally present on the T cell surface complexed with the components which make up T3. In the case of beta chain, multiple somatic DNA rearrangements bring together V beta (variable), D beta (diversity) and J beta (joining) gene segments before a mature messenger RNA can be transcribed. So far beta chain genes have been extensively studied in the human and in the mouse system and we have very little information on other mammals. Our aims were to obtain information that may provide a structural basis for understanding developmental as well as evolutionary aspects of the TCR gene system in mammals. In this study we compare the hybridization pattern between a human cDNA probe coding for the beta chain constant region and restricted genomic DNA extracted from lymphocytes deriving from human as well as from rat and lamb. The comparison of the hybridization data represent a first piece of information about the variation of the structure of the TCR beta chain genes in mammals
Cloning and cDNA sequence of the rat X-chromosome linked phosphoglycerate kinase
No full textThis paper reports the isolation and the sequence determination of rat phosphoglycerate kinase (PGK) cDNA clones. This cDNA, derived from an X-linked PGK gene transcript, contains a reading frame of 1254 nt and 5' and 3' non coding regions of 40 and 380 nt respectively. Analysis of the nucleotide sequence at the three codon position shows a biased codon usage with a prevalence of the triplet G non G N. Comparison of the inferred rat amino acid sequence with that of other organisms makes possible the calculation of the unit evolutionary period (UEP) for this enzyme, placing it at around 40 million years (My). Thus PGK is one of the oldest housekeeping enzymes
Isolation and characterization of variable region of thymus T cell receptor genes in sheep
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Testicular cells lysostripped of H-Y antigen organize ovarian follicle-like aggregates
No full textA suspension of free testicular cells were obtained by mild trypsin treatment from newborn BALB/c testes, and their plasma membrane H-Y antigen sites were blocked (lysostripped) by an excess of H-Y antibody of proven specificity and potency (45 min in ice). Upon 16 h of the Moscona-type rotation culture, these treated testicular cells yielded primarily spherical aggregates, more than half of which demonstrated a strong resemblance to ovarian follicles. The resemblance was particularly striking between the smallest testicular folliculoids and primordial ovarian follicles that abound in the newborn female gonad. Under the same condition, control serum-treated testicular cells primarily yielded cylindrical tubular structures that can be very long. Over a critical range, concentrations of H-Y antibody apparently influenced the frequency of testicular folliculoid formation. The above directly supports the proposed testis-organizing function of H-Y antigen and is certainly compatible with the genetic situation encountered in the wood lemming (Myopus schisticolor), that in the functional absence of H-Y antigen, XY gonadal cells readily organize an ovary
Evolution of T-cell receptors gamma and delta constant region and other T-cell related proteins in the human-rodent-artiodactyl triplet
No full textIn this paper we report a detailed comparative and evolutionary analysis of the sequences of constant T-cell receptor (Tcr) C gamma delta genes of artiodactyls compared to the homologous sequences of rodents and primates. Because of the frequency and physiological distribution of gamma delta T-cells in different animals, rodents and humans are defined as "gamma delta low" species and ruminants as "gamma delta high" species. Such a characteristic seems to be due to an adaptive role of gamma delta T-cell function. By analyzing the ruminant gene phylogeny of Tcr C gamma we were able to estimate the distance between cattle and sheep at 18 million years ago, a time that is in agreement with other nonmolecular estimates. For Tcr C gamma delta genes a peculiar phylogenetic relationship was found, with human and mouse clustering together and leaving artiodactyls apart. By using appropriate outgroups, the same phylogenetic pattern was obtained with other T-cell related sequences: namely, Tcr C alpha chain, CD3 gamma and delta invariant subunits. Interleukin-2. Interleukin-2 receptor alpha chain and Interleukin-1 beta with the exception of Tcr C beta chain and Interleukin-1 alpha. In contrast, the analysis of all other T-cell nonrelated genes, available in primary databases reveals a different tree, where primates and artiodactyls are sister taxa and rodents are apart in accordance with the current view of mammalian phylogeny. These data are relevant to important evolutionary issues. They show how misleading a phylogeny based on a single or on a few homologous genes may be. In addition they demonstrate that genes with correlated functions may evolve in a lineage specific manner probably in relation to environmental conditions
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