Skipping of exons by premature termination of transcription and alternative splicing within intron-5 of the sheep SCF gene: a novel splice variant

Endocrine-disrupting chemicals affect sertoli TM4 cell functionality through dysregulation of gap junctional intercellular communication in vitro

The frequencies of adverse outcomes associated with male reproductive health, including infertility and testicular cancer, are increasing. These adverse trends are partially attributed to increased exposure to environmental agents such as endocrine-disrupting chemicals (EDCs). This study addresses effects on EDCs on adjacent prepubertal Sertoli TM4 cells, specifically on 1) testicular gap junctional intercellular communication (GJIC), one of the hallmarks of non-genotoxic carcinogenicity, 2) GJIC building blocks connexins (Cx), and 3) mitogen-activated protein kinases MAPKs. We selected eight representatives of EDCs: bisphenol A and organochlorine chemicals such as pesticides dichlorodiphenyltrichloroethane, lindane, methoxychlor, and vinclozolin, industrial chemical 2,2',4,4',5,5'-hexachlorobiphenyl, and components of personal care products, triclocarban and triclosan. EDCs rapidly dysregulated GJIC in Sertoli TM4 cells mainly via MAPK p38 and/or Erk1/2/pathways by the intermediate hyper- or de-phosphorylation of Cx43 (Ser368, Ser282) and translocalization of Cx43 from the plasma membrane, suggesting disturbed intracellular trafficking of Cx43 protein. Surprisingly, EDCs did not rapidly activate MAPK Erk1/2 or p38; on the contrary, TCC and TCS decreased their activity (phosphorylation). Our results indicate that EDCs might disrupt testicular homeostasis and development via testicular GJIC, junctional and non-junctional functions of Cx43 and MAPK-signalling pathways in Sertoli cells.

Exon-1 skipping and intron-1 retaining by alternative splicing of the c-KIT gene encodes a novel splice variant in the skin of Merino sheep (Ovis aries)

c-KIT, a type III receptor protein tyrosine kinase, plays an essential role in melanocyte development, migration, and survival. Mutations within the c-KIT gene are previously shown to cause the white coat color phenotypes in pigs, mice, goats, and humans. However, up so far, the splicing isoform(s), genomic architecture of c-KIT have not been characterized well in merino sheep. Reverse transcriptase (RT)-PCR analysis with molecular prediction identified two basic splice variants: Transcript Variant-1, 2 for 12 bp insertion coding sequences (CDS) corresponding to the four amino acids 'GNSK', respectively. Using 5' RACE, here we report for the first time a novel c-KIT 'Transcript Variant-3' from the skin of merino sheep by comparative genome analyses at exon(1)-intron(1)-exon(2) boundaries. In contrast, a single product of 795 bp was characterized by 3' RACE. We also demonstrated that the c-KIT gene expression at the transcript level is not mediated via an intron-9 splicing event. Overall, beyond what was observed in other mammals, our data provide novel insights into the molecular structure of the c-KIT gene in sheep.

Genetic variants in macrophage colony-stimulating factor are associated with risk of renal cell carcinoma in a Chinese population

OBJECTIVE

This study was performed to investigate whether CSF-1 polymorphisms influenced the risk of renal cell carcinoma in a Chinese population.

METHODS

The potentially functional polymorphisms in CSF-1 (rs333951 and rs2050462) were genotyped in this hospital-based case-control study, comprising 1512 renal cell carcinoma patients and 1691 controls in a Chinese population using the TaqMan assay. Furthermore, odds ratios (ORs) and 95% confidence intervals (CI) were used to estimate such an association. The logistic regression was used to assess the association between these genetic polymorphisms and the risk of renal cell carcinoma.

RESULTS

We found the genotype and allele frequency distribution of rs2050462 were significantly associated with the increasing risk of renal cell carcinoma ( P = 0.007). However, no statistical significance was found in the association between CSF-1 rs333951 polymorphism and the susceptibility of renal cell carcinoma ( P = 0.589). The analysis of combined risk alleles revealed that patients with two to four risk alleles showed no elevated risk of renal cell carcinoma compared to those with zero to one risk alleles (adjusted OR 1.09; 95% CI 0.95, 1.26; P = 0.226). Furthermore, compared with the genotypes containing A allele (AC and AA), the patients carrying the CC genotype in rs2050462 had a significantly greater prevalence of clinical stage II and IV (adjusted OR 0.67; 95% CI 0.47, 0.94; P = 0.021; adjusted OR 0.50; 95% CI 0.29, 0.88; P = 0.015, respectively).

CONCLUSIONS

The functional rs2050462 in CSF-1 might have a substantial influence on the renal cell carcinoma susceptibility and evolution in the Chinese population.

miR-1207-5p suppresses lung cancer growth and metastasis by targeting CSF1

We previously reported that miR-1207-5p can inhibit epithelial-mesenchymal transition (EMT) induced by growth factors such as EGF and TGF-β, but the exact mechanism is unclear. Here we identified that Colony stimulating factor 1 (CSF1) is a target gene of miR-1207-5p. CSF1 controls the production, differentiation and function of macrophage and promotes the release of proinflammatory chemokines. We showed that miR-1207-5p inhibited lung cancer cell A549 proliferation, migration and invasion in vitro, and suppressed the STAT3 and AKT signalings. miR-1207-5p overexpression can increase HUVEC angiogenesis, and can modulate the M2 phenotype of macrophage. miR-1207-5p also significantly inhibited A549 cells metastasis in a nude mouse xenograft model. miR-1207-5p and CSF1 expression levels and their relationship with lung cancer survival and metastasis status were assayed by means of a lung cancer tissue microarray. Macrophage is an essential part of the tumor microenvironment, thus the miR-1207-5p-CSF1 axis maybe a new regulator of lung cancer development through modulating the tumor microenvironment.

Alternative splicing of the sheep MITF gene: novel transcripts detectable in skin

Microphthalmia-associated transcription factor (MITF) is a basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factor, which regulates the differentiation and development of melanocytes and pigment cell-specific transcription of the melanogenesis enzyme genes. Though multiple splice variants of MITF have been reported in humans, mice and other vertebrate species, in merino sheep (Ovis aries), MITF gene splicing has not yet been investigated until now. To investigate the sheep MITF isoforms, the full length mRNA/cDNAs from the skin of merino sheep were cloned, sequenced and characterized. Reverse transcriptase (RT)-PCR analysis and molecular prediction revealed two basic splice variants with (+) and without (-) an 18 bp insertion viz. CGTGTATTTTCCCCACAG, in the coding region (CDS) for the amino acids 'ACIFPT'. It was further confirmed by the complete nucleotide sequencing of splice junction covering intron-6 (2463 bp), wherein an 18bp intronic sequence is retained into the CDS of MITF (+) isoform. Further, full-length cDNA libraries were enriched by the method of 5' and 3' rapid amplification of cDNA ends (RACE-PCR). A total of seven sheep MITF splice variants, with distinct N-terminus sequences such as MITF-A, B, E, H, and M, the counterparts of human and mouse MITF, were identified by 5' RACE. The other two 5' RACE products were found to be novel splice variants of MITF and represented as 'MITF truncated form (Trn)-1, 2'. These alternative splice (AS) variants were illustrated using comparative genome analysis. By means of 3' RACE three different MITF 3' UTRs (625, 1083, 3167bp) were identified and characterized. We also demonstrated that the MITF gene expression determined at transcript level is mediated via an intron-6 splicing event. Here we summarize for the first time, the expression of seven MITF splice variants with three distinct 3' UTRs in the skin of merino sheep. Our data refine the structure of the MITF gene in sheep beyond what was previously known in humans, mice, dogs and other mammals.