RESUMEN
Keratin IF (KRT) and keratin-associated protein genes encode the majority of wool and hair proteins. We have identified cDNA sequences representing nine novel sheep KRT genes, increasing the known active genes from eight to 17, a number comparable to that in the human. However, the absence of KRT37 in the type I family and the discovery of type II KRT87 in sheep exemplify species-specific compositional differences in hair KRT genes. Phylogenetic analysis of hair KRT genes within type I and type II families in the sheep, cattle and human genomes revealed a high degree of consistency in their sequence conservation and grouping. However, there were differences in the fibre compartmentalisation and keratinisation zones for the expression of six ovine KRT genes compared with their human orthologs. Transcripts of three genes (KRT40, KRT82 and KRT84) were only present in the fibre cuticle. KRT32, KRT35 and KRT85 were expressed in both the cuticle and the fibre cortex. The remaining 11 genes (KRT31, KRT33A, KRT33B, KRT34, KRT36, KRT38-39, KRT81, KRT83 and KRT86-87) were expressed only in the cortex. Species-specific differences in the expressed keratin gene sets, their relative expression levels and compartmentalisation are discussed in the context of their underlying roles in wool and hair developmental programmes and the distinctive characteristics of the fibres produced.
Asunto(s)
Expresión Génica/genética , Queratinas/clasificación , Queratinas/genética , Ovinos/genética , Ovinos/metabolismo , Animales , Secuencia de Bases/genética , Bovinos , ADN Complementario/genética , Folículo Piloso/metabolismo , Humanos , Queratinocitos/metabolismo , Queratinas Específicas del Pelo/clasificación , Queratinas Específicas del Pelo/genética , Queratinas Tipo I/clasificación , Queratinas Tipo I/genética , Queratinas Tipo II/clasificación , Queratinas Tipo II/genética , Anotación de Secuencia Molecular , Datos de Secuencia Molecular , Filogenia , Homología de Secuencia de Ácido Nucleico , Piel/metabolismo , Lana/química , Lana/crecimiento & desarrolloRESUMEN
Keratins make up the largest subgroup of intermediate filaments and, in chordates, represent the most abundant proteins in epithelial cells. Senegalese sole (Solea senegalensis) is a commercially important flatfish in which only two type I keratin genes, sseKer1 and sseKer2, have been described. We obtained the entire cDNAs encoding for a novel type II keratin, referred to as sseKer3. Main features and sequence identities with other fish and mammalian type II keratins are described. Expression profiles during larval development and in juvenile tissues were analyzed using a real-time PCR approach. In juvenile fish, sseKer3 was strongly expressed in gills, intestine, skin and stomach. During metamorphosis climax a drop in sseKer3 expression was observed. Transcriptional regulation of sseKer3 by thyroid hormones (THs) was also evaluated. Larvae exposed to the goitrogen thiourea (TU) exhibited higher mRNA levels than untreated control. Moreover, adding exogenous T4 hormone to TU-treated larvae restored or even reduced the sseKer3 transcript levels with respect to the untreated control. The possible role of keratins in osmotic stress response was evaluated in juvenile gills exposed to three different water salinities (15, 37 and 60psu). Whereas no significant changes in sseKer2 expression were detected; sseKer1 was early (12h) up-regulated at hypo-osmotic conditions and sseKer3 was down-regulated both at low and high salinity after 24h and 48h. Their possible role is discussed.
Asunto(s)
Peces Planos/genética , Regulación del Desarrollo de la Expresión Génica , Queratinas Tipo II/genética , Salinidad , Secuencia de Aminoácidos , Animales , Peces Planos/clasificación , Peces Planos/metabolismo , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Queratinas Tipo II/clasificación , Queratinas Tipo II/metabolismo , Larva/genética , Larva/crecimiento & desarrollo , Larva/metabolismo , Metamorfosis Biológica/genética , Metamorfosis Biológica/fisiología , Datos de Secuencia Molecular , Filogenia , Alineación de Secuencia , Hormonas Tiroideas/farmacologíaRESUMEN
AIMS: To investigate the use of immunohistochemistry in distinguishing necrotizing sialometaplasia (NSM) from squamous cell (SCC) and mucoepidermoid carcinoma (MEC) by (i) the identification of myoepithelial cells and (ii) cytokeratin (CK) expression. METHODS AND RESULTS: Thirteen cases with the histological changes of NSM, eight SCCs and eight MECs were examined with the following immunohistochemical markers: calponin, S100, smooth muscle actin (SMA), p63, CK7, CK5, CK6 and CAM5.2. The distribution and intensity of staining were recorded. Residual myoepithelial cells (best demonstrated by calponin and SMA) were identified at the periphery of the epithelial islands in all cases of NSM (although not in all islands), in contrast to MEC and SCC. S100 showed a similar pattern, although staining fewer cells. Moderate rather than extensive expression of CK7 may help to distinguish NSM from MEC. CONCLUSION: Identification of myoepithelial cells and CK7 expression may help to distinguish NSM from its mimics.
