A homologue of pancreatic trypsin is localized in the acrosome of mammalian sperm and is released during acrosome reaction.
We have identified cDNA and genomic clones encoding a homologue of pancreatic trypsin, termed TESP4, as a candidate protein involved in the sperm penetration of the egg zona pellucida in mouse. The deduced amino acid sequence indicates that TESP4 is 90% identical to pancreatic trypsin. Analysis of Northern blotting and reverse transcriptase-polymerase chain reaction reveals that the mouse TESP4 gene is ubiquitously expressed in all tissues tested, including the pancreas and testis, and the transcript is present in the haploid stages of male germ cells. Moreover, immunochemical analysis of mouse cauda epididymal sperm using an affinity-purified antibody against bovine pancreatic trypsinogen shows that TESP4 is localized only in the sperm acrosome and is released during the acrosome reaction induced by calcium ionophore A23187. These findings may open a new point of view regarding the molecular mechanisms of the sperm/egg interactions, including the sperm penetration of the egg zona pellucida.
Ohmura
K
K
Institute of Applied Biochemistry, University of Tsukuba, Tsukuba Science City, Ibaraki 305-8572, Japan.
Kohno
N
N
Kobayashi
Y
Y
Yamagata
K
K
Sato
S
S
Kashiwabara
S
S
Baba
T
T
D000177:Acrosome / Q000201:enzymology*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D003001:Cloning, Molecular; D005091:Exons; D007150:Immunohistochemistry; D007438:Introns; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010179:Pancreas / Q000201:enzymology; D012333:RNA, Messenger / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry / Q000235:genetics*; D014357:Trypsin / Q000737:chemistry; D014362:Trypsinogen / Q000276:immunology; D015044:Zona Pellucida / Q000378:metabolism
D012333:RNA, Messenger; D000001:Calcimycin; D014362:Trypsinogen; D012697:Serine Endopeptidases; C122160:Try4 protein, mouse; D014357:Trypsin; D002118:Calcium