Multimerization of Drosophila sperm protein Mst77F causes a unique condensed chromatin structure.
Despite insights on the cellular level, the molecular details of chromatin reorganization in sperm development, which involves replacement of histone proteins by specialized factors to allow ultra most condensation of the genome, are not well understood. Protamines are dispensable for DNA condensation during Drosophila post-meiotic spermatogenesis. Therefore, we analyzed the interaction of Mst77F, another very basic testis-specific protein with chromatin and DNA as well as studied the molecular consequences of such binding. We show that Mst77F on its own causes severe chromatin and DNA aggregation. An intrinsically unstructured domain in the C-terminus of Mst77F binds DNA via electrostatic interaction. This binding results in structural reorganization of the domain, which induces interaction with an N-terminal region of the protein. Via putative cooperative effects Mst77F is induced to multimerize in this state causing DNA aggregation. In agreement, overexpression of Mst77F results in chromatin aggregation in fly sperm. Based on these findings we postulate that Mst77F is crucial for sperm development by giving rise to a unique condensed chromatin structure.
Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
Nils
N
Kost
Developmental Biology, FB17, Philipps University, 35037 Marburg, Germany.
Sophie
S
Kaiser
Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
Yogesh
Y
Ostwal
Electron Microscopy Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
Dietmar
D
Riedel
Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
Alexandra
A
Stützer
Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
Miroslav
M
Nikolov
Developmental Biology, FB17, Philipps University, 35037 Marburg, Germany.
Christina
C
Rathke
Developmental Biology, FB17, Philipps University, 35037 Marburg, Germany.
Renate
R
Renkawitz-Pohl
Laboratory of Chromatin Biochemistry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany wfischl@gwdg.de.
Wolfgang
W
Fischle
D000818:Animals; D030801:Animals, Genetically Modified; D002843:Chromatin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008297:Male; D016297:Mutagenesis, Site-Directed; D011479:Protamines / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism; D055672:Static Electricity
D002843:Chromatin; D029721:Drosophila Proteins; D006657:Histones; C503323:Mst77F protein, Drosophila; D011479:Protamines; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D004247:DNA