RESUMEN
During the process of spermatogenesis, the proliferation of spermatogonia (stem cell descendants) is replaced by their differentiation in growing spermatocytes responsible for the preparation to meiosis, which is accompanied by a cardinal change in transcriptional programs. We have demonstrated that, in drosophila, this process is accompanied by a splash of the expression of ß-subunit of nascent polypeptide-associated complex (NAC) associated by ribosomes. Nascent polypeptide-associated complex is known as a chaperone involved in co-translational protein folding. This is the first case of the detection of tissue-specific co-translational NAC cofactor in multicellular eukaryotes. It is proposed that spermatocyte specific NAC is involved in the modulation of the expression of the proteins that provide the functioning of subsequent stages of spermatogenesis.
Asunto(s)
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Regulación del Desarrollo de la Expresión Génica , Chaperonas Moleculares/genética , Espermatocitos/metabolismo , Testículo/metabolismo , Animales , Diferenciación Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/metabolismo , Masculino , Meiosis , Chaperonas Moleculares/metabolismo , Biosíntesis de Proteínas , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Ribosomas/genética , Ribosomas/metabolismo , Espermatocitos/crecimiento & desarrollo , Espermatocitos/ultraestructura , Espermatogénesis/genética , Testículo/crecimiento & desarrolloRESUMEN
Human serum albumin (HSA) is the most abundant protein in plasma. Cys34, the only free Cys residue, is the predominant plasma thiol and a relevant sacrificial antioxidant. Both in vivo circulating HSA and pharmaceutical preparations are heterogeneous with respect to the oxidation state of Cys34. In this work, we developed an external pH gradient chromatofocusing procedure that allows the analysis of the oxidation status of HSA in human plasma and biopharmaceutical products based on the different apparent isoelectric points and chemical properties of the redox isoforms. Specifically, reduced-mercury blocked HSA (HSA-SHg(+)), HSA with Cys34 oxidized to sulfenic acid (HSA-SOH) and HSA oxidized to sulfinate anion (HSA-SO2(-)) can be separated with resolutions of 1.4 and 3.1 (first and last pair) and hence quantified and purified. In addition, an N-terminally degraded isoform (HSA3-585) in different redox states can be resolved as well. Confirmation of the identity of the chromatofocusing isolated isoforms was achieved by high resolution whole protein MS. It is proposed that the chromatofocusing procedure can be used to produce more exact and complete descriptions of the redox status of HSA in vivo and in vitro. Finally, the scalability capabilities of the chromatofocusing procedure allow for the preparation of highly pure standards of several redox isoforms of HSA.