Evolutionary conservation of lampbrush-like loops in drosophilids.
BACKGROUND
Loopin-1 is an abundant, male germ line specific protein of Drosophila melanogaster. The polyclonal antibody T53-F1 specifically recognizes Loopin-1 and enables its visualization on the Y-chromosome lampbrush-like loop named kl-3 during primary spermatocyte development, as well as on sperm tails. In order to test lampbrush-like loop evolutionary conservation, extensive phase-contrast microscopy and immunostaining with T53-F1 antibody was performed in other drosophilids scattered along their genealogical tree.


RESULTS
In the male germ line of all species tested there are cells showing giant nuclei and intranuclear structures similar to those of Drosophila melanogaster primary spermatocytes. Moreover, the antibody T53-F1 recognizes intranuclear structures in primary spermatocytes of all drosophilids analyzed. Interestingly, the extent and conformation of the staining pattern is species-specific. In addition, the intense staining of sperm tails in all species suggests that the terminal localization of Loopin-1 and its orthologues is conserved. A comparison of these cytological data and the data coming from the literature about sperm length, amount of sperm tail entering the egg during fertilization, shape and extent of both loops and primary spermatocyte nuclei, seems to exclude direct relationships among these parameters.


CONCLUSIONS
Taken together, the data reported strongly suggest that lampbrush-like loops are a conserved feature of primary spermatocyte nuclei in many, if not all, drosophilids. Moreover, the conserved pattern of the T53-F1 immunostaining indicates that a Loopin-1-like protein is present in all the species analyzed, whose localization on lampbrush-like loops and sperm tails during spermatogenesis is evolutionary conserved.
Piergentili
Roberto
R
Dipartimento di Genetica e Biologia Molecolare, Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185 Rome, Italy. roberto.piergentili@uniroma1.it
D000818:Animals; D000906:Antibodies; D005075:Biological Evolution; D029721:Drosophila Proteins / Q000032:analysis* / Q000235:genetics; D004331:Drosophila melanogaster; D018428:Drosophilidae; D007150:Immunohistochemistry; D008297:Male; D009687:Nuclear Proteins / Q000032:analysis* / Q000235:genetics; D013090:Spermatocytes / Q000737:chemistry* / Q000648:ultrastructure; D013091:Spermatogenesis; D014998:Y Chromosome
D000906:Antibodies; D029721:Drosophila Proteins; D009687:Nuclear Proteins
Annu Rev Genet. 1980;14:121-44
6260016
Genetics. 1916 Jan;1(1):1-52
17245850
J Cell Biol. 1982 May;93(2):365-73
6807996
Genetics. 1988 Dec;120(4):1015-34
2465201
Chromosoma. 1985;92(4):273-82
3930172
Genetics. 1991 Sep;129(1):177-89
1936957
Genetics. 1993 Mar;133(3):569-79
8454204
Proc Natl Acad Sci U S A. 1993 Dec 1;90(23):11132-6
8248219
Chromosoma. 1990 Aug;99(4):260-6
2119983
Nature. 1996 Feb 1;379(6564):405-6
8559245
Mol Phylogenet Evol. 2005 Oct;37(1):15-24
16182148
Int Rev Cytol. 1987;109:211-58
3323107
Nature. 1995 May 11;375(6527):109
7753164
Nature. 1995 May 4;375(6526):20
7723836
Proc Natl Acad Sci U S A. 2000 Nov 21;97(24):13239-44
11069293
Chromosoma. 1981;83(4):507-21
6791901
Proc Natl Acad Sci U S A. 2001 Nov 6;98(23):13225-30
11687639
Nature. 1996 Jun 27;381(6585):783-5
8657280
J Biol Chem. 2006 Aug 25;281(34):24728-36
16790438
Proc Natl Acad Sci U S A. 1995 Apr 25;92(9):3804-8
7731987
Chromosoma. 1980;80(3):253-75
6777121
Int Rev Cytol. 1990;123:129-75
2289847
Cold Spring Harb Symp Quant Biol. 1978;42 Pt 2:1121-35
98264
Mech Dev. 2000 Jun;94(1-2):171-81
10842068
Genetica. 2004 Mar;120(1-3):233-44
15088661
Cell. 1982 Dec;31(3 Pt 2):655-70
6819086
Chromosoma. 2004 Oct;113(4):188-96
15338233
Trends Genet. 1995 May;11(5):195-200
7785079
Evol Dev. 2002 Jul-Aug;4(4):303-15
12168622
Proc Natl Acad Sci U S A. 1995 Nov 7;92(23):10614-8
7479851
Chromosoma. 1976 Sep 24;57(4):377-86
63359
Experientia. 1991 Jan 15;47(1):111-4
1999238
Cell. 1983 Jun;33(2):529-41
6407757
Genome. 1989;31(2):561-71
2561109
Chromosoma. 1996 Dec;105(5):285-92
8939821
Genetics. 1998 Jul;149(3):1363-76
9649526
Proc Biol Sci. 1995 Feb 22;259(1355):105-10
7732034
Proc Natl Acad Sci U S A. 1982 Dec;79(23):7405-9
6818544
Nature. 1978 Mar 16;272(5650):249-51
628449
J Cell Sci. 1994 Dec;107 ( Pt 12):3521-34
7706403
Nat Genet. 2006 Dec;38(12):1440-5
17099714