AI Article Synopsis
- The study focuses on the intercalary heterochromatin region 75C1-2 in Drosophila's 3L chromosome, revealing its structure through electron microscopy as three condensed bands.
- The mapped region is approximately 445 kb in length, and while the SUUR protein binds to the entire area, only the proximal part shows full polytenization, indicating an asymmetric underreplication zone in the distal half.
- The research suggests that intercalary heterochromatin regions in Drosophila may be organized into three distinct types based on the localization of underreplication zones.
Article Abstract
In Drosophila polytene chromosomes, regions of intercalary heterochromatin are scattered throughout the euchromatic arms. Here, we present data on the first fine analysis of the individual intercalary heterochromatin region, 75C1-2, located in the 3L chromosome. By using electron microscopy, we demonstrated that this region appears as three closely adjacent condensed bands. Mapping of the region on the physical map by means of the chromosomal rearrangements with known breakpoints showed that the length of the region is about 445 kb. Although it seems that the SUUR protein binds to the whole 75C1-2 region, the proximal part of the region is fully polytenized, so the DNA underreplication zone is asymmetric and located in the distal half of the region. Finally, we speculate that intercalary heterochromatin regions of Drosophila polytene chromosomes are organized into three different types with respect to the localization of the underreplication zone.
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| http://dx.doi.org/10.1007/s00412-009-0232-6 | DOI Listing |
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