TY - JOUR
T1 - Molecular cloning and chromosomal localization of Chinese hamster telomeric protein chTRF1. Its potential role in chromosomal instability
AU - Smilenov, Lubomir B.
AU - Mellado, Wilfredo
AU - Rao, Pulivarthi H.
AU - Sawant, Satin G.
AU - Umbricht, Christopher B.
AU - Sukumar, Saraswati
AU - Pandita, Tej K.
N1 - Funding Information:
This work was supported by NIH NS34746 and Columbia Cancer Center Breast Cancer Research Program. Sincere thanks are due to Drs Jerry W Shay and Theodore T Puck for their advice and comments. Thanks are due to Drs EE Marcantonio and Titia de Lange for providing the expression vectors and 371C2 antibody.
PY - 1998/10/22
Y1 - 1998/10/22
N2 - Chinese hamster cells frequently have altered karyotypes. To investigate the basis of recent observations that karyotypic alterations are related to telomeric fusions, we asked whether these alterations are due to lack of telomere repeat binding factor/s. Further, Chinese hamster chromosomes contain large blocks of interstitial telomeric repeats, which are preferentially involved in chromosome breakage and exchange, rendering it an interesting model for such studies. Here, we report on the cloning and the chromosomal localization of the Chinese hamster telomere repeat binding factor, chTRF1. The sequence analysis revealed, similar to human TRF1 (hTRF1), an N-terminal acidic domain, a TRF1 specific DNA binding motif and a C-terminal Myb type domain. Unlike mouse TRF1 (mTRF1), chTRF1 shows 97.5% identity to hTRF1. chTRF1 gene was localized on the long arm of chromosome 5. In vitro translation of chTRF1 resulted in protein product similar in molecular weight to hTRF1. Immunostaining of Chinese hamster ovary cells (CHO) with anti-TRF1 antibody revealed punctate nuclear staining. At metaphase, antibodies failed to detect TRF1 on most of the chromosome ends and the interstitial telomeric repeat bands. These studies suggest that chTRF1 does not bind the interstitial telomeric repeats, and its presence at the metaphase chromosome ends is limited. The later could be a factor contributing to frequent karyotypic alterations observed in Chinese hamster cells.
AB - Chinese hamster cells frequently have altered karyotypes. To investigate the basis of recent observations that karyotypic alterations are related to telomeric fusions, we asked whether these alterations are due to lack of telomere repeat binding factor/s. Further, Chinese hamster chromosomes contain large blocks of interstitial telomeric repeats, which are preferentially involved in chromosome breakage and exchange, rendering it an interesting model for such studies. Here, we report on the cloning and the chromosomal localization of the Chinese hamster telomere repeat binding factor, chTRF1. The sequence analysis revealed, similar to human TRF1 (hTRF1), an N-terminal acidic domain, a TRF1 specific DNA binding motif and a C-terminal Myb type domain. Unlike mouse TRF1 (mTRF1), chTRF1 shows 97.5% identity to hTRF1. chTRF1 gene was localized on the long arm of chromosome 5. In vitro translation of chTRF1 resulted in protein product similar in molecular weight to hTRF1. Immunostaining of Chinese hamster ovary cells (CHO) with anti-TRF1 antibody revealed punctate nuclear staining. At metaphase, antibodies failed to detect TRF1 on most of the chromosome ends and the interstitial telomeric repeat bands. These studies suggest that chTRF1 does not bind the interstitial telomeric repeats, and its presence at the metaphase chromosome ends is limited. The later could be a factor contributing to frequent karyotypic alterations observed in Chinese hamster cells.
KW - chTRF1
KW - Identity
KW - Localization
UR - http://www.scopus.com/inward/record.url?scp=0032558792&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032558792&partnerID=8YFLogxK
U2 - 10.1038/sj.onc.1202138
DO - 10.1038/sj.onc.1202138
M3 - Article
C2 - 9798685
AN - SCOPUS:0032558792
VL - 17
SP - 2137
EP - 2142
JO - Oncogene
JF - Oncogene
SN - 0950-9232
IS - 16
ER -