High impact information on Meiotic Prophase I

• Exonuclease I (Exo I) from Schizosaccharomyces pombe, a 5'-->3' double-stranded DNA exonuclease, is induced during meiotic prophase I [1].
• Anti-REC-8 immunostaining decorated synaptonemal complexes (SCs) at pachytene and chromosomal axes in bivalents and univalents at diakinesis [2].
• Thus, murine Msh5 promotes synapsis of homologous chromosomes in meiotic prophase I [3].
• The presence of both Rad51 and Lim15 proteins as discrete foci on leptotene and zygotene chromosomes and their colocalization suggest that meiotic recombination begins at the leptotene stage with the cooperation of these proteins and continues in zygotene [4].
• These results argue strongly that homolog interactions during meiotic prophase I require a novel meiosis-specific cyclin in Arabidopsis [5].
• Telomeres cluster on the nuclear envelope during meiotic prophase, to create the bouquet [6].

Biological context of Meiotic Prophase I

• In evl-14 mutants, synaptonemal complexes (SCs) were detectable but more than the usual six DAPI (4',6'-diamidino-2-phenylindole)-positive structures were seen at diakinesis, suggesting that EVL-14/PDS-5 is important for the maintenance of sister chromatid cohesion in late prophase [7].
• The Atm and Atr proteins are mitotic cell-cycle proteins that also associate with chromatin during meiotic prophase I [8].
• At later stages, diakinesis and metaphase I, Rec8 was localized along the interstitial axes of chromosomes, including both centromere and arm regions of chromosomes [9].
• Immunocytology against a centromeric histone H3 variant revealed that PAIR2 remains at centromeres until diakinesis, by which time the homologous centromeres had already been synapsed [10].
• Immunofluorescence results suggest that a cohesin complex containing Rad21 and STAG2 cooperates with a STAG3-specific complex to maintain sister chromatid cohesion during the diplotene stage of meiosis [11].

Anatomical context of Meiotic Prophase I

• Although the mutation never affected homologous chromosome pairing and chiasma maintenance, the development of pollen mother cells was arrested at various stages of meiotic prophase I, which resulted in complete male sterility [12].
• Xenopus oocytes are arrested in meiotic prophase I and resume meiotic divisions in response to progesterone [13].
• As bivalents in spermatocytes, but not oocytes, begin to desynapse at diplonema they are often held together at these Rad51-positive termini [14].
• RT-PCR and in situ hybridization analyses of a time course of juvenile testis development indicate that Spo11 expression begins in early meiotic Prophase I, prior to the pachytene stage, with increasing accumulation of mRNA through the pachytene stage [15].
• The results demonstrate that mRNA encoding follistatin is located in many germ cells including type B spermatogonia, primary spermatocytes with the exception of the late leptotene and early zygotene stages, and spermatids at steps 1 to 11 [16].

Associations of Meiotic Prophase I with chemical compounds

• Metaphase-I oocytes had higher resting pHi levels than prophase-I oocytes and showed no significant pHi changes after addition of 5-HT [17].
• For analysis of chiasmata frequency and localization in the diplotene/diakinesis stages the resolution of FPG and acridine orange staining was comparable to that of BAT [18].
• When female golden hamsters were treated with cadmium chloride at the oogenesis stages of diakinesis/metaphase I to metaphase II, oocytes with the chromosomal complements of hyperhaploidy and diploidy, as well as oocytes at the anaphase-I stage, were observed [19].
• A small number of testis-ova at the zygotene stage was seen on the sixth day after the beginning of treatment with estradiol, and on the 12th day testis-ova at the pachytene and diplotene stages were observed [20].
• Effect of actinomycin D on the quail oocyte nucleolus during meiotic prophase I [21].

Gene context of Meiotic Prophase I

• Transcription of the Sycp1 gene (synaptonemal complex protein 1) starts as early as the leptotene and zygotene stages [22].
• The pattern of expression during spermatogenesis is consistent with a role for MSH4 both during zygonema and pachynema [23].
• To phenocopy daf-21 mutations, we impaired the daf-21 function by RNA interference (RNAi), and found that oocytes skipped the diakinesis arrest and displayed a defective diakinesis arrest, which led to the production of endomitotic oocytes with polyploid chromosomes (Emo phenotype) [24].
• The highest level of Tcfl5 protein was found in primary spermatocytes at the diplotene stage of meiotic prophase, where the protein colocalizes with transcriptionally active chromatin [25].
• In scc-3 mutant animals, normal SCs were not visible and approximately 24 DAPI-positive structures were seen at diakinesis, indicating that SCC-3 is necessary for sister chromatid cohesion [7].

Analytical, diagnostic and therapeutic context of Meiotic Prophase I

• In most cases, SC karyotyping provides additional information and permits the detection and analysis of aberrations that are not revealed in diakinesis [26].

References