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ARS Home » Midwest Area » West Lafayette, Indiana » Crop Production and Pest Control Research » Research » Publications at this Location » Publication #118724
Title: PHYSICAL LOCATION OF A HSP70 GENE HOMOLOGUE ON THE CENTROMERE OF CHROMOSOME1B OF WHEAT (TRITICUM AESTIVUM L.)

Author
item FRANCKI, MICHAEL - PURDUE UNIVERSITY
item BERZONSKY, WILLIAM - PURDUE UNIVERSITY
item OHM, HERBERT - PURDUE UNIVERSITY
item Anderson, Joseph

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Centromeres are important structures of chromosomes because they are responsible for the proper segregation of chromosomes during cell division and reproduction. However, little is known about the DNA organization of centromeres. In this study, wheat lines which contain a chromosome consisting of wheat and rye DNA joined together at the centromere were used to obtain further information about the nature of centromeric DNA sequences. Using DNA markers, a gene was identified which was located in the centromere of the group 1B wheat chromosome. This gene is actively expressed in leaf tissue and is induced by heat and light stimuli. Prior to this study, most of the previously identified DNA sequences located in plant centromeres were shown to be present in many copies. The presence of many copies of these different DNA sequences has made it very difficult to determine their function and how these DNA sequences are arranged in the centromere. Identification of this centromeric gene that is present in one copy and actively expressed will enable a more complete characterization of a wheat centromere and lead to a greater understanding of the structure and function of centromeres. This research, by identifying a gene that is present in one copy in the centromere and actively expressed, will enable scientists to obtain a more complete characterization of a wheat centromere and will lead to a greater understanding of the structure and function of centromeres.

Technical Abstract: The centromere is an important structure enabling proper segregation of chromosomes. However, little is known about the DNA organization of centromeres. In this study, wheat-rye translocation lines were used to physically map 1BL.1RS centric breakpoints and molecular probes to obtain further information on the nature of centromeric DNA sequences. The results, using the rye centromeric sequence pAWRC.1, indicated that 1BL.1RS contains a small portion of the centromere from 1R of wheat. Further studies used molecular markers to identify centromeric sequences on wheat group 1 chromosomes. Selections of RFLP markers, clustered around the centromere of wheat homoeologous group-1S chromosomes, were chosen as probes for Souther blot hybridization. One marker, PSR161, identified a small 1BS segment in all 1BL.1RS lines. This segment maps proximal to pAWRC.1 in 1BL.1RS and on the centromere of 1B. Sequence analysis of PSR161 shows high homology to HSP70 genes. RNA analyses shows this gene i constitutively expressed in leaf tissue and is induced by heat shock and light stimuli. Identification of this gene located in the centromeric heterochromation will also enable us to physically characterize a wheat centromere as well as determine the function of the protein encoded by this gene under different environmental stimuli.