RESUMEN
Using a sample of Chinese firms, we examine stock market reaction to firms that announce a change in their product lines to those related to COVID-19 management (medical masks and ventilators, among others). We find the market reacts positively to the announcements. In addition, when a firm ordinarily has a large share of export sales, the stock market reaction is more salient, indicating that export sales provide a certification effect that positively signals investors. Additional analysis on moderating effects suggest that, conditional on foreign sales, prior experience with medical product lines or less uncertainty about supply availability enhances the cumulative announcement returns (CARs), while the adverse impact of firm size on CAR magnifies.
RESUMEN
We examine the effectiveness of a new approach of using a direct inspection program on all environmental laws on the firm-level environmental investment in China. The direct inspection program is a response to the continued pollution issues despite the increased effort in the actions of regulatory agencies and their agents. Our findings suggest that firms located in direct inspection cities perform better than those located in non-direct inspection cities in terms of environmental investments. The findings are robust to a battery of robustness checks. Using dynamic analysis, we find that the effect of the direct inspection program lasts at least two years. Our further analysis shows that firms in direct inspection cities respond better to environmental enforcement and non-stated owned firms receive more subsidies than firms in non-direct inspection program cities. The major take away from our analysis is that, in emerging economies, it is more effective to go directly to the city level to enhance the actions of regulatory agencies and their agents. Cutting layers of agencies can enhance firm-level environmental investment.
RESUMEN
Glycogen synthase kinase-3 beta (GSK-3 beta) regulates cell metabolism, cell cycle, and cell fate through the phosphorylation of a diverse array of substrates. Herein, we provide evidence that supports a role for GSK-3 in mammalian meiosis and spermatogenesis. Immunostaining of testis sections showed that while GSK-3 alpha was ubiquitous in the seminiferous tubules, GSK-3 beta was expressed in premeiotic type B spermatogonia, in both meiotic preleptotene and leptotene spermatocytes, as well as in Sertoli cells in both the mouse and rat. Thus, GSK-3 beta is expressed in germ cells entering meiosis. In addition, intense immunoreactivity was detected in rat step 6 though 11 spermatids. In situ hybridization (ISH) in rat testis confirmed the immunostaining pattern in leptotene and spermatids and showed a GSK-3 beta messenger RNA (mRNA) signal in some pachytene spermatocytes. The restricted pattern of expression suggests cell-specific regulation of Gsk-3 beta mRNA. To determine whether GSK-3 is required for meiosis entry, rat stage VIIa seminiferous tubule segments were cultured with selective small-molecule GSK-3 inhibitors. These compounds markedly and dose-dependently suppressed meiotic synthesis (S)-phase DNA. Since a yeast GSK-3 homolog, Rim11p (regulator of inducer of meiosis), is pivotal to meiosis entry, we tested whether GSK-3 beta complements Rim11p function in meiosis. Rim11p phosphorylates transcription factors Ume6p (unscheduled meiotic gene expression) and Ime1p (inducer of meiosis) to induce meiosis entry. Overexpression of murine GSK-3 beta in a rim11 mutant yeast failed to rescue the sporulation defect. Our finding that GSK-3 beta interacted only with Ume6p but not with IME1 in a yeast 2-hybrid assay suggests that noncomplementation reflects partial divergence in substrate specificity. This work provides the basis for future studies of GSK-3 beta signaling in mammalian meiosis and spermatogenesis.
Asunto(s)
Glucógeno Sintasa Quinasa 3/fisiología , Proteínas Represoras , Espermatogénesis/fisiología , Testículo/metabolismo , Secuencia de Aminoácidos , Animales , Northern Blotting , Western Blotting , Proteínas de Unión al ADN/fisiología , Glucógeno Sintasa Quinasa 3 beta , Hibridación in Situ , Péptidos y Proteínas de Señalización Intracelular , Masculino , Meiosis/efectos de los fármacos , Meiosis/fisiología , Ratones , Datos de Secuencia Molecular , Proteínas Nucleares/fisiología , Técnicas de Cultivo de Órganos , Proteínas Serina-Treonina Quinasas/genética , Ratas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteínas de Saccharomyces cerevisiae/fisiología , Túbulos Seminíferos/efectos de los fármacos , Túbulos Seminíferos/fisiología , Homología de Secuencia de Aminoácido , Espermatogénesis/efectos de los fármacos , Espermatozoides/metabolismo , Factores de Transcripción/fisiología , Técnicas del Sistema de Dos Híbridos , Levaduras/genéticaRESUMEN
We have previously shown that a ubiquitously expressed RNA splicing factor, RNA-binding motif 7 (RBM7), cloned from a testis complementary DNA library, enhances messenger RNA (mRNA) splicing in vitro and is expressed in a cell-restricted fashion. Herein, we detail its mRNA and protein expression in the rodent testis. RNA in situ hybridization shows that Rbm7 expression in rat germ cells closely parallels the entry and progression of meiosis. The expression commences in type B spermatogonia, it rises during the preleptotene stage, peaks in leptotene spermatocytes, and declines afterward, but increases again in stage-associated pachytene spermatocytes. An affinity-purified polyclonal antibody raised against a peptide corresponding to amino acids 202-224 of the mouse RBM7 recognized the predicted 35 kd protein both in testicular lysates and in in vitro translation reactions. Consistent with the in situ hybridization results, RBM7 immunoreactivity was also detected in type B spermatogonia, spanned the entire period of spermatocyte development, and extended to round and early elongated spermatids. Moreover, RBM7 appeared nuclear up to the mid pachytene stage and became cytoplasmic thereafter. Consistent with its role in RNA splicing, yeast 2-hybrid and glutathione S-transferase pull-down assays show that RBM7 interacts with splicing factor 3b subunit 2 (SAP145), and with the splicing regulator, SRp20. These interactions and the nuclear localization of RBM7 provide insights into its function in pre-mRNA processing in developing spermatocytes during entry into meiosis and progression through the meiotic prophase.