testes in situ hybridization the protamine domain
The protamine gene cluster is home to at least three genes, protamine 1(PRM1), protamine 2 (PRM2) and transition protein 2 (TNP2). It resides on syntenic regions of human and mouse chrmosome 16. These genes are essential for the correct re-packaging of the haploid genome during late spermatogenesis (i.e. spermiogenesis, the morphological transition from round spermatid to mature spermatozoan). During this phase, the transition proteins disrupt the nucleosomal chromatin structure, temporarily displacing the histones and replacing them with the basic, cysteine-rich protamines. This leads to a higher degree of chromatin compaction,  essential for the small  and  transcriptionally  inert

sperm nucleus. The protamine domain is tightly regulated: it is potentiated in pachytene-staged spermatocytes, transcribed in round spermatids and tranlated in elongating spermatids only. Our focus in the Krawetz lab is understanding what epigenetic mechanisms (e.g. gene potentiation, interactions with the nuclear matrix, histone acetylation, DNA methylation) are at play in the regulation of this group of genes, and how the impact of these factors may change throughout differentiation to mature spermatozoa.                           more on the protamines more on the protamines...

Repackaging chromatin: a model of chromatin
repackaging from the solenoid loop in somatic
cells (left) to the annuloid loop seen in sperm
(right). [modified from: Nat Gen 28: 10-12]

chromatin repackaging


Krawetz, S.A. and Dixon G.H. (1984) Isolation and in vitro translation of a mammalian protamine mRNA. Bioscience Reports 4:593-603. [PubMed]

Aiken, J.M., Miller, F.D., Hagen, F., McKenzie, D.I., Krawetz, S.A., van de Sande, J.H., Rattner, J.B. and Dixon, G.H. (1985) Tandem repeats of a specific alternating purine-pyrimidine DNA sequence adjacent to protamine genes in the rainbow trout that can exist in the Z-conformation. Biochemistry 24:6268-6276. [PubMed]

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Krawetz, S.A., Connor, W. and Dixon, G.H. (1988) Bovine protamine genes contain a single intron: the structures of the two alleles. The Journal of Biological Chemistry 263:321-326. [PubMed]

Krawetz, S.A. and Dixon, G.H. (1988) Sequence similarities of the protamine genes: implications for regulation and evolution. The Journal of Molecular Evolution 27:291-297. [PubMed]

Krawetz, S.A., Herfort, M.H., Hamerton, J.L., Pon, R.T. and Dixon, G.H. (1989) Chromosomal localization and structure of the human P1 protamine gene. Genomics 5:639-645. [PubMed]

Nelson, J.E. and Krawetz, S.A. (1993) Linkage of human spermatid-specific basic nuclear protein genes: definition and evolution of the P1>P2>TP2 locus. The Journal of Biological Chemistry 268:2932-2936. [PubMed]

De Jonckheere, J., Nelson, J.E., Ginsburg, K.A., Martin, L., Krawetz, S.A. (1994) GA repeat polymorphism at the PRM2 male fertility locus of chromosome 16. Human Molecular Genetics 3: 1915. [PubMed]

Wykes, S.M., Nelson, J.E., Visscher, D.W., Djakiew, D. and Krawetz, S.A. (1995) Coordinate expression of the PRM1, PRM2 and TNP2 multigene locus in human testis. DNA and Cell Biology 14:155-161. [PubMed]

Nelson, J.E. and Krawetz, S.A. (1995) Mapping the clonally unstable recombinogenic PRM1>PRM2>TNP2 region of human 16p13.2. DNA Sequence 5:163-168. [PubMed]

Choudhary, S. K, Wykes, S.M., Kramer, J.A., Mohamed, A.N., Koppitch, F., Nelson, J.E. and Krawetz, S.A. (1995) A Haploid expressed gene cluster exists as a single chromatin domain in human sperm. The Journal of Biological Chemistry 270:8755-8762. [PubMed]

Kramer, J.A. and Krawetz, S.A. (1995) Matrix associated regions in haploid expressed domains. Mammalian Genome 6:677-679. [PubMed]

Nelson, J.E. and Krawetz, S.A. (1995) Computer assisted promoter analysis of a human sperm specific nucleoprotein gene cluster. DNA Sequence 5:329-337.[PubMed]

Kramer, J.A. and Krawetz, S.A. (1996) Analysis of transgenes by Polymerase Chain Reaction: establishing and maintaining the PRM1>PRM2>TNP2 line. Analytical Biochemistry 235:110-111. [PubMed]

Kramer, J.A. and Krawetz, S.A. (1996) Nuclear matrix interactions within the sperm genome. The Journal of Biological Chemistry 271:11619-11622. [PubMed]

Macauley, S.P., Schultz, G.S., Bruckner, B.A., Krawetz, S.A. and Yang, T.P. (1996) Effects of transforming growth factor alpha-1 on extracellular matrix gene expression by human fibroblasts from a laryngeal stenotic lesion. Wound Repair and Regeneration 4:269-277.

Wykes, S.M., Visscher, D.M. and Krawetz, S.A. (1997) Haploid expressed transcripts persist in mature human spermatozoa. Molecular Human Reproduction 3:15-19. [PubMed]

Kramer, J.A., Adams, M.D., Singh, G.B., Doggett, N.A. and Krawetz, S.A. (1998) Extended Analysis of the Region Encompassing the PRM1>PRM2>TNP2 Domain: Genomic Organization, Evolution and Gene identification. Journal of Experimental Zoology 282:245-253. [PubMed]

Kramer, J.A., Adams, M.D., Singh, G.B., Doggett, N.A. and Krawetz, S.A. (1998) A matrix associated region localizes the human SOCS-1 gene to chromosome 16p13.13. Somatic Cell and Molecular Genetics 24:131-133. [PubMed]

Kramer, J.A. and Krawetz, S.A. (1998) Genesis of a novel human sequence from the human protamine PRM1 gene. Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 120:467-473. [PubMed]

Kramer, J.A., McCarrey, J. R., Djakiew, D. and Krawetz, S.A. (1998) Differentiation: the selective potentiation of chromatin domains. Development 125:4749-4755. [PubMed]

Stewart, K., Kramer, J.A., Evans, M.I. and Krawetz, S.A. (1999) Temporal expression of the transgenic human protamine gene cluster. Fertility and Sterility 71:739-745. [PubMed]

Schmid, C., Heng, H.H.Q., Rubin, C., Ye, C.J. and Krawetz S.A. (2001) Sperm nuclear matrix association of the PRM1>PRM2>TNP2 domain is independent of Alu Methylation, Human Molecular Reproduction 7:903-911. [PubMed]


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