KIT variants in bovine ovarian cells and corpus luteum.
We report the presence of KIT variants in granulosa and thecal cells of the follicle and endothelial and steroidogenic cells of the corpus luteum. Transcripts of both full-length splice variants, KIT and KITA, were ubiquitously detected in all cell types, in contrast to transcripts for truncated KIT. RT-PCR with exon-intron-specific primers suggested that KIT transcripts retained intron sequences. We used domain-specific KIT antibodies to identify truncated KIT proteins in cell conditioned media and lysates. These proteins represented soluble KIT and a so far disregarded intracellular KIT fragment, and were ubiquitously present. In contrast, glycosylated variants of full-length KIT were predominantly detected in thecal and endothelial cells. All KIT variants were encountered again in COS-7 cells transfected with a vector containing KITA. Phorbol 12-myristate-13-acetate treatment induced levels of truncated KITs, and this effect was repressed by the metalloproteinase inhibitor TAPI-1. Our findings show that ectodomain cleavage of full-length KIT generates an intracellular KIT. Our experiments suggest that replenishing full-length KIT differs among various ovarian cell types.
Koch
Daniela
D
Institute of Anatomy, University of Leipzig, Leipzig, Germany.
Sakurai
Michiharu
M
Hummitzsch
Katja
K
Hermsdorf
Thomas
T
Erdmann
Sabine
S
Schwalbe
Steffen
S
Stolzenburg
Jens-Uwe
JU
Spanel-Borowski
Katharina
K
Ricken
Albert M
AM
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002417:Cattle; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003338:Corpus Luteum / Q000166:cytology / Q000378:metabolism*; D017931:DNA Primers / Q000235:genetics; D005260:Female; D015571:Follicular Fluid / Q000378:metabolism; D014644:Genetic Variation; D006031:Glycosylation; D006107:Granulosa Cells / Q000378:metabolism; D007438:Introns; D010053:Ovary / Q000166:cytology / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D019009:Proto-Oncogene Proteins c-kit / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012995:Solubility; D013799:Theca Cells / Q000378:metabolism; D014162:Transfection
D017931:DNA Primers; D010446:Peptide Fragments; D012333:RNA, Messenger; D019009:Proto-Oncogene Proteins c-kit