Uncoupling transcription and translation through miRNA-dependent poly(A) length control in haploid male germ cells.

As one of the post-transcriptional regulatory mechanisms, uncoupling of transcription and translation plays an essential role in development and adulthood physiology. However, it remains elusive how thousands of mRNAs get translationally silenced while stability is maintained for hours or even days before translation. In addition to oocytes and neurons, developing spermatids display significant uncoupling of transcription and translation for delayed translation. Therefore, spermiogenesis represents an excellent in vivo model for investigating the mechanism underlying uncoupled transcription and translation. Through full-length poly(A) deep sequencing, we discovered dynamic changes in poly(A) length through deadenylation and re-polyadenylation. Deadenylation appeared to be mediated by microRNAs (miRNAs), and transcripts with shorter poly(A) tails tend to be sequestered into ribonucleoprotein (RNP) granules for translational repression and stabilization. In contrast, re-polyadenylation might allow for translocation of the translationally repressed transcripts from RNP granules to polysomes. Overall, our data suggest that miRNA-dependent poly(A) length control represents a previously unreported mechanism underlying uncoupled translation and transcription in haploid male mouse germ cells.

[Association of surfactant protein D gene polymorphisms at rs3088308 and rs721917 with susceptibility to silicosis].

OBJECTIVE: To investigate the relationship between polymorphisms of surfactant protein D (rs3088308 and rs721917) and the susceptibility to silicosis. METHODS: This case-control study included 125 silicosis patients and 125 individuals exposed to industrial dust but without silicosis (control group), who were strictly matched with the case group for age, gender, work type and cumulative length of dust exposure. The rs3088308 and rs721917 polymorphisms of surfactant protein-D were detected in all the participants using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: The frequencies of T/T, T/A and A/A genotypes of surfactant protein-D rs3088308 locus were 22.2%, 71.2% and 5.6% in the case group, significantly different from the frequencies of 17.6%, 58.4% and 24.0% in the control group, respectively (P<0.05). The frequencies of C/C, C/T and T/T genotypes of rs721917 locus were 17.6%, 56.8% and 25.6% in the case group, similar to the frequencies of 15.2%, 60.0% and 24.8% in the control group, respectively (P>0.05). CONCLUSION: Surfactant protein-D rs3088308 polymorphism is significantly associated with silicosis, and the T allele may be a risk factor for silicosis in individuals exposed to industrial dust.