Activity and inactivity of moth sex chromosomes in somatic and meiotic cells

• Published in: Chromosoma Vol. 128; no. 4; pp. 533 - 545
• Main Authors: Traut, W., Schubert, V., Daliková, M., Marec, F., Sahara, K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2019; Springer Nature B.V
• Subjects: Animal Genetics and Genomics; Animals; Biochemistry; Biomedical and Life Sciences; Bombyx - genetics; Bombyx - metabolism; Bombyx mori; Cell Biology; Chromatin; Chromatin - metabolism; Chromosomes; Chromosomes, Insect - metabolism; Developmental Biology; DNA-directed RNA polymerase; Eukaryotic Microbiology; Human Genetics; Labeling; Life Sciences; Meiosis; Microscopy; Moths - genetics; Moths - metabolism; Original Article; Pachytene; RNA polymerase; Sex chromosomes; Sex Chromosomes - metabolism; Somatic cells; Transcription; Uridine; W chromosomes; Z chromosomes; MSCI; Heterochromatin; Sex chromatin; Germline-limited activity; Ephestia; Bombyx
• ISSN: 0009-5915; 1432-0886
• DOI: 10.1007/s00412-019-00722-8

Moths and butterflies (Lepidoptera) are the most species-rich group of animals with female heterogamety, females mostly having a WZ, males a ZZ sex chromosome constitution. We studied chromatin conformation, activity, and inactivity of the sex chromosomes in the flour moth Ephestia kuehniella and the silkworm Bombyx mori , using immunostaining with anti-H3K9me2/3, anti-RNA polymerase II, and fluoro-uridine (FU) labelling of nascent transcripts, with conventional widefield fluorescence microscopy and ‘spatial structured illumination microscopy’ (3D-SIM). The Z chromosome is euchromatic in somatic cells and throughout meiosis. It is transcriptionally active in somatic cells and in the postpachaytene stage of meiosis. The W chromosome in contrast is heterochromatic in somatic cells as well as in meiotic cells at pachytene, but euchromatic and transcriptionally active like all other chromosomes at postpachytene. As the W chromosomes are apparently devoid of protein-coding genes, their transcripts must be non-coding. We found no indication of ‘meiotic sex chromosome inactivation’ (MSCI) in the two species.