Chromomere Number and Its Genetic Significance in Lampbrush Chromosomes

Overview

Journal Chromosoma

Specialty Molecular Biology

Date 1975 Jan 1

PMID 1097213

Citations 11

Authors

M Vlad

H C MACGREGOR

Affiliations

Soon will be listed here.

Abstract

The chromosomes of three species of salamander belonging to the genus Plethodon have been studied with regard to the absolute length of the haploid set of lampbrush chromosomes and the number and distribution of chromomeres per laploid set of lampbrush chromosomes. Each aspect has been considered in relation to the substantial difference in genome size between P. cinereus (C = 20 pg), P. vehiculum (C = 36.8 pg) and P. dunni (C = 38.8 pg). --Karyotype analyses carried out on unfixed preparations of lampbrush chromosomes showed that the absolute length of a haploid complement of lampbrush chromosomes from medium-sized yolky oocytes is much greater for P. vehiculum and P. dunni than for P. cinereus. Nonetheless, the relative dimensions of chromosomes are nearly identical in all three species. --Chromomers were counted along the whole length of the 14th (shortest) bivalent, and the total number of chromomeres in the haploid set of lampbrush chromosomes was determined by extrapolation on the basis of the known relative length of the 14th bivalent in the respective species. Chromomeres were also counted in measured segments of undamaged lampbrush preprations in which all chromosomes could be clearly identified. The average distance between chromomeres (chromomere distribution) was determined and the total chromomere number was estimated on the basis of measured total length of lampbrush chromosomes in a preparation. Chromomere distribution is the same for lampbrush chromosomes from all 3 species, and since P. vehiculum and P. dunni have longer chromosomes than P. cinereus, it is clear that the former 2 species have many more chromomeres (60-70%) per haploid set of lampbrush chromosomes. The term chromomere was used here in the descriptive sense to define a discrete granule of deoxyribonucleoprotein on the axis of a lampbrush chromosome.--These findings are discussed in relation to what is known of the molecular organization of eukaryotic genomes, and in relation to ideas on gene action and transcription in lampbrush chromosomes.

Citing Articles

Assignment of the somatic A/B compartments to chromatin domains in giant transcriptionally active lampbrush chromosomes.

Krasikova A, Kulikova T, Rodriguez Ramos J, Maslova A Epigenetics Chromatin. 2023; 16(1):24.

PMID: 37322523 PMC: 10268536. DOI: 10.1186/s13072-023-00499-2.

Comparison of the somatic TADs and lampbrush chromomere-loop complexes in transcriptionally active prophase I oocytes.

Kulikova T, Maslova A, Starshova P, Rodriguez Ramos J, Krasikova A Chromosoma. 2022; 131(4):207-223.

PMID: 36031655 DOI: 10.1007/s00412-022-00780-5.

New Insights Into Chromomere Organization Provided by Lampbrush Chromosome Microdissection and High-Throughput Sequencing.

Zlotina A, Maslova A, Pavlova O, Kosyakova N, Al-Rikabi A, Liehr T Front Genet. 2020; 11:57.

PMID: 32127797 PMC: 7038795. DOI: 10.3389/fgene.2020.00057.

Herbert Macgregor (1933-2018).

Gall J Chromosome Res. 2018; 26(4):225-231.

PMID: 30276581 PMC: 6360096. DOI: 10.1007/s10577-018-9586-z.

Chromomeres revisited.

Macgregor H Chromosome Res. 2012; 20(8):911-24.

PMID: 22956230 DOI: 10.1007/s10577-012-9310-3.

References

Grossbach U . [Chromosome activity and biochemical cell differentiation in the salivary glands of Camptochironomus]. Chromosoma. 1969; 28(2):136-87. DOI: 10.1007/BF00331528. View

PELLING C . [RIBONUCLEIC ACID SYNTHESIS IN GIANT CHROMOSOMES. AUTORADIOGRAPHIC INVESTIGATIONS ON CHIRONOMUS TENTANS]. Chromosoma. 1964; 15:71-122. DOI: 10.1007/BF00326915. View

Rayle R, Green M . A contribution to the genetic fine structure of the region adjacent to white in Drosophila melanogaster. Genetica. 1968; 39(3):497-507. DOI: 10.1007/BF02324482. View

MILLER Jr O, Hamkalo B . Visualization of RNA synthesis on chromosomes. Int Rev Cytol. 1972; 33:1-25. DOI: 10.1016/s0074-7696(08)61446-1. View

Clarkson S, Birnstiel M, Purdom I . Clustering of transfer RNA genes of Xenopus laevis. J Mol Biol. 1973; 79(2):411-29. DOI: 10.1016/0022-2836(73)90014-4. View

Shannon M, Kaufman T, Shen M, Judd B . Lethality patterns and morphology of selected lethal and semi-lethal mutations in the zeste-white region of Drosophila melanogaster. Genetics. 1972; 72(4):615-38. PMC: 1212859. DOI: 10.1093/genetics/72.4.615. View

Breuer M, Pavan C . Behavior of polytene chromosomes of Rhynchosciara angelae at different stages of larval development. Chromosoma. 1955; 7(4):341-86. View

Gall J, CALLAN H . H3 uridine incorporation in lampbrush chromosomes. Proc Natl Acad Sci U S A. 1962; 48:562-70. PMC: 220816. DOI: 10.1073/pnas.48.4.562. View

Davidson E, HOUGH B, Amenson C, Britten R . General interspersion of repetitive with non-repetitive sequence elements in the DNA of Xenopus. J Mol Biol. 1973; 77(1):1-23. DOI: 10.1016/0022-2836(73)90359-8. View

10.

Keyl H . A demonstrable local and geometric increase in the chromosomal DNA of Chironomus. Experientia. 1965; 21(4):191-3. DOI: 10.1007/BF02141878. View

11.

Jelinek W, Molloy G, Fernandez-Munoz R, Salditt M, Darnell J . Secondary structure in heterogeneous nuclear RNA: involvement of regions from repeated DNA sites. J Mol Biol. 1974; 82(3):361-70. DOI: 10.1016/0022-2836(74)90597-x. View

12.

Mizuno S, MACGREGOR H . Chromosomes, DNA sequences, and evolution in salamanders of the genus Plethodon. Chromosoma. 1974; 48(3):239-96. DOI: 10.1007/BF00326507. View

13.

Clarkson S, Birnstiel M, Serra V . Reiterated transfer RNA genes of Xenopus laevis. J Mol Biol. 1973; 79(2):391-410. DOI: 10.1016/0022-2836(73)90013-2. View

14.

MACGREGOR H, Kezer J . Gene amplification in oocytes with 8 germinal vesicles from the tailed frog Ascaphus truei Stejneger. Chromosoma. 1970; 29(2):189-206. DOI: 10.1007/BF00326078. View

15.

Ashburner M, Chihara C, Meltzer P, Richards G . Temporal control of puffing activity in polytene chromosomes. Cold Spring Harb Symp Quant Biol. 1974; 38:655-62. DOI: 10.1101/sqb.1974.038.01.070. View

16.

GOWEN J, Gay E . Gene Number, Kind, and Size in Drosophila. Genetics. 1933; 18(1):1-31. PMC: 1208367. DOI: 10.1093/genetics/18.1.1. View

17.

Britten R, Kohne D . Repeated sequences in DNA. Hundreds of thousands of copies of DNA sequences have been incorporated into the genomes of higher organisms. Science. 1968; 161(3841):529-40. DOI: 10.1126/science.161.3841.529. View

18.

CALLAN H . The organization of genetic units in chromosomes. J Cell Sci. 1967; 2(1):1-7. DOI: 10.1242/jcs.2.1.1. View

19.

Beermann W . [Chromomore constancy and specific modifications of the chromosome structure in development and organ differentiation of Chironomus tentans]. Chromosoma. 1952; 5(2):Unknown. View

20.

Judd B, Shen M, Kaufman T . The anatomy and function of a segment of the X chromosome of Drosophila melanogaster. Genetics. 1972; 71(1):139-56. PMC: 1212768. DOI: 10.1093/genetics/71.1.139. View