Asynchronous expression of the homeodomain protein CUX1 in Sertoli cells and spermatids during spermatogenesis in mice.
The homeodomain CUX1 protein exists as multiple isoforms that arise from proteolytic processing of a 200-kDa protein or an alternate splicing or from the use of an alternate promoter. The 200-kDa CUX1 protein is highly expressed in the developing kidney, where it functions to regulate cell proliferation. Transgenic mice ectopically expressing the 200-kDa CUX1 protein develop renal hyperplasia associated with reduced expression of the cyclin kinase inhibitor p27. A 55-kDa CUX1 isoform is expressed exclusively in the testes. We determined the pattern and timing of CUX1 protein expression in developing testes. CUX1 expression was continuous in Sertoli cells from prepubertal testes but became cyclic when spermatids appeared. In testes from mature mice, CUX1 was highly expressed only in round spermatids at stages IV-V of spermatogenesis, in both spermatids and Sertoli cells at stages VI-X of spermatogenesis, and only in Sertoli cells at stage XI of spermatogenesis. While most of the seminiferous tubules in wild-type mice were between stages VI and X of spermatogenesis, there was a significant reduction in the percentage of seminiferous tubules between stages VI and X in Cux1 transgenic mice and a significant increase in the percentage of seminiferous tubules in stages IV-V and XI. Moreover, CUX1 was not expressed in proliferating cells in testes from either wild-type or transgenic mice. Thus, unlike the somatic form of CUX1, which has a role in cell proliferation, the testis-specific form of CUX1 is not involved in cell division and appears to play a role in signaling between Sertoli cells and spermatids.
Kroll
Melissa R
MR
Department of Biology, Dordt College, Sioux Center, Iowa, USA.
Viss
Engela S
ES
Lamb
Jonathan
J
Horstman
Joy
J
Powell
Alexander
A
Van Wyk
Andrea
A
Hinkkala
Kaarlo
K
Hoogland
Traci
T
Schippers
Matthew
M
Shannon
Stephen
S
Carlton
Carol G
CG
Sharma
Madhulika
M
Taylor
Aaron
A
Vanden Heuvel
Gregory B
GB
Jelsma
Tony N
TN
D000818:Animals; D002450:Cell Communication / Q000235:genetics / Q000502:physiology; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D012708:Sertoli Cells / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D013087:Spermatids / Q000378:metabolism* / Q000502:physiology; D013091:Spermatogenesis / Q000235:genetics* / Q000502:physiology; D013737:Testis / Q000166:cytology / Q000378:metabolism / Q000502:physiology
C000624101:Cux1 protein, mouse; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins