The Small ubiquitin-related modifier （SUMO） conjugation to a variety of proteins regulates diverse cellular processes, including transcription, cell cycle regulation and maintenance of genome integrity. To investiga...The Small ubiquitin-related modifier （SUMO） conjugation to a variety of proteins regulates diverse cellular processes, including transcription, cell cycle regulation and maintenance of genome integrity. To investigate in vivo biological function of SUMO paralogs, we inactivated them in the early development of zebrafish. While zebrafish embryos deficient for all three SUMO paralogs, as Ubc9-deficient ones, displayed severe defects, loss of individual SUMO paralog was compatible with a normal development. SUMO-deficient embryos can be rescued by a single human or zebrafish SUMO. While key structural basic lysine residues and N-terminal unstructured stretch of SUMO are critical for in vivo rescue, the consensus Kll sumoylation site of SUMO2 is dispensable, implying that chain formation on this potential site is unessential for normal development. Inactivation of all three SUMOs triggered p53- dependent apoptosis and further inactivation of p53 restored normal zebrafish development. Interestingly, we also demonstrate that the dominant negative truncated form of p53, Δ113p53, significantly blunts SUMO depletion-induced p53 activity in vivo. Taken together, our results suggest that SUMO paralogs are indispensable, but redundant, in the early development of zebrafish.展开更多
Spinal muscular atrophy(SMA)is caused by dysfunction of the alpha motor neurons of the spinal cord.It is an autosomal recessive disease associated to the SMN1 gene,located in the subtelomeric region of 5q13.A paralog ...Spinal muscular atrophy(SMA)is caused by dysfunction of the alpha motor neurons of the spinal cord.It is an autosomal recessive disease associated to the SMN1 gene,located in the subtelomeric region of 5q13.A paralog SMN2 gene is located at the centromeric region of the same chromosome,which apparently originated by an ancestral inverted duplication occurring only in humans.The exon sequence differs in two nucleotides in exon 7 and exon 8,which leads to an SMN2 transcript that lacks exon 7 and results in a truncated protein.Part(10%)of the SMN2 transcripts avoids the splicing of exon 7 but most of the copies are dysfunctional.In a disease scenario,the more SMN2 copies the higher possibility to restore at least partly the effects of SMN1 deficiency.Some therapeutic approaches are being developed to increase the expression of SMN2.To determine the number of SMN1 and SMN2 copies,the methodology must distinguish accurately between both genes.In this work,we present the results obtained using multiplex ligation-dependent probe amplification(MLPA)in 60 SMA suspected patients/carriers derived from different regions of Argentina.In 32 of these DNA samples we found alterations in SMN1.Among these,16 presented a heterozygous deletion(carrier status)and 14 an homozygous deletion(patient status)in exon 7 and 8 of SMN1.In one case,exon 7 was found homozygously deleted but exon 8 presented a single copy,and in another case,exon 7 was found heterozygously deleted while exon 8 was normal.Almost half of the patients(7/15)presented a normal diploid number of SMN2 while the other half(8/15)presented an increased number.In this work we showed how a probe-based methodology such as MLPA was able to distinguish between the paralog genes and determine the amount of copies in DNA samples from suspected patients/carriers of SMA.展开更多
基金Supplementary information is linked to the online version of the paper on the Cell Research website.Acknowledgements We thank Dr Jiang Zhu （Shanghai institute of hematology, Rui Jin hospital） and Dr Nelly Kieffer （CNRS LIA, Rui Jin hospital） for their comments. This work was supported by grants from the National High Tech Program of China （863, 2006AA02Z150）, the National Science Foundation of China （30525006）, the Science and Technology Commission of Shanghai Municipality （07XD14022, 06PJ14068）, ATIP program and BNP PARIBAS.
文摘The Small ubiquitin-related modifier （SUMO） conjugation to a variety of proteins regulates diverse cellular processes, including transcription, cell cycle regulation and maintenance of genome integrity. To investigate in vivo biological function of SUMO paralogs, we inactivated them in the early development of zebrafish. While zebrafish embryos deficient for all three SUMO paralogs, as Ubc9-deficient ones, displayed severe defects, loss of individual SUMO paralog was compatible with a normal development. SUMO-deficient embryos can be rescued by a single human or zebrafish SUMO. While key structural basic lysine residues and N-terminal unstructured stretch of SUMO are critical for in vivo rescue, the consensus Kll sumoylation site of SUMO2 is dispensable, implying that chain formation on this potential site is unessential for normal development. Inactivation of all three SUMOs triggered p53- dependent apoptosis and further inactivation of p53 restored normal zebrafish development. Interestingly, we also demonstrate that the dominant negative truncated form of p53, Δ113p53, significantly blunts SUMO depletion-induced p53 activity in vivo. Taken together, our results suggest that SUMO paralogs are indispensable, but redundant, in the early development of zebrafish.
文摘Spinal muscular atrophy(SMA)is caused by dysfunction of the alpha motor neurons of the spinal cord.It is an autosomal recessive disease associated to the SMN1 gene,located in the subtelomeric region of 5q13.A paralog SMN2 gene is located at the centromeric region of the same chromosome,which apparently originated by an ancestral inverted duplication occurring only in humans.The exon sequence differs in two nucleotides in exon 7 and exon 8,which leads to an SMN2 transcript that lacks exon 7 and results in a truncated protein.Part(10%)of the SMN2 transcripts avoids the splicing of exon 7 but most of the copies are dysfunctional.In a disease scenario,the more SMN2 copies the higher possibility to restore at least partly the effects of SMN1 deficiency.Some therapeutic approaches are being developed to increase the expression of SMN2.To determine the number of SMN1 and SMN2 copies,the methodology must distinguish accurately between both genes.In this work,we present the results obtained using multiplex ligation-dependent probe amplification(MLPA)in 60 SMA suspected patients/carriers derived from different regions of Argentina.In 32 of these DNA samples we found alterations in SMN1.Among these,16 presented a heterozygous deletion(carrier status)and 14 an homozygous deletion(patient status)in exon 7 and 8 of SMN1.In one case,exon 7 was found homozygously deleted but exon 8 presented a single copy,and in another case,exon 7 was found heterozygously deleted while exon 8 was normal.Almost half of the patients(7/15)presented a normal diploid number of SMN2 while the other half(8/15)presented an increased number.In this work we showed how a probe-based methodology such as MLPA was able to distinguish between the paralog genes and determine the amount of copies in DNA samples from suspected patients/carriers of SMA.
