DNM1DN: a new class of paralogous genomic segments (duplicons) with highly conserved copies on chromosomes Y and 15
ANNALS OF HUMAN GENETICS
Authors: Makrinou, E; Fox, M; Wolfe, J; Cameron, J; Taylor, K; Edwards, YH
Abstract
Screening a testis cDNA selection library for Y-linked genes yielded 79 cDNAs. Of these, 9 matched the 3' region of the dynamin 1 gene (DNM1) on chromosome 9q34 with >90% identity. Fluoresence in situ hybridisation and PCR amplification were used to localise a large number of DNM1-like sequences to human chromosomes 15 and Y PCR amplification of overlapping Y-linked YACs allowed a more accurate mapping of the Y-linked DNM1-like cDNAs to a euchromatic locus in close proximity to heterochromatin at Yq11.23. A search of the genome database identified 64 highly homologous copies of the DNM1 fragment. Most of these copies were localised to chromosomes 15 and Y, but others mapped to chromosomes 5, 8, 10, 12, 19 and 22. These sequences exhibit all the major features of a duplicon and have been designated DNM1DN (DNM1 duplicon). Evolutionary studies using fluorescence in situ hybridisation indicate that transposition of the DNM1DN sequence to chromosome 15 took place earlier in primate evolution than the transposition to the Y chromosome. The translocation to the Y took place at a time following the divergence of a common ancestor from gorilla, approximately 4-7 million years ago.
A novel motif in the yeast mitochondrial dynamin Dnm1 is essential for adaptor binding and membrane recruitment
JOURNAL OF CELL BIOLOGY
Authors: Bui, Huyen T.; Karren, Mary A.; Bhar, Debjani; Shaw, Janet M.
Abstract
To initiate mitochondrial fission, dynamin-related proteins (DRPs) must bind specific adaptors on the outer mitochondrial membrane. The structural features underlying this interaction are poorly understood. Using yeast as a model, we show that the Insert B domain of the Dnm1 guanosine triphosphatase (a DRP) contains a novel motif required for association with the mitochondrial adaptor Mdv1. Mutation of this conserved motif specifically disrupted Dnm1-Mdv1 interactions, blocking Dnm1 recruitment and mitochondrial fission. Suppressor mutations in Mdv1 that restored Dnm1-Mdv1 interactions and fission identified potential protein-binding interfaces on the Mdv1 beta-propeller domain. These results define the first known function for Insert B in DRP-adaptor interactions. Based on the variability of Insert B sequences and adaptor proteins, we propose that Insert B domains and mitochondrial adaptors have coevolved to meet the unique requirements for mitochondrial fission of different organisms.